Method and apparatus for identifying user in radio access network communication system

ABSTRACT

A method and an apparatus for identifying a user in a radio access network (RAN), and a first node in the wireless communication system are provided. The method includes identifying a unique identifier of a UE, identifying a radio access network (RAN) UE identifier of the UE, and transmitting information related to a mapping relation between the RAN UE identifier and the unique identifier of the UE to a second node, based on the unique identifier of the UE.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application of prior application Ser.No. 16/927,361, filed on Jul. 13, 2020, which will be issued as U.S.Pat. No. 11,464,056, on Oct. 4, 2022, which is based on and claimedpriority under 35 U.S.C. § 119(e) of a U.S. Provisional application Ser.No. 62/873,452, filed on Jul. 12, 2019, in the U.S. Patent and TrademarkOffice, and § 119(a) of a Korean patent application number10-2019-0086026, filed on Jul. 16, 2019, in the Korean IntellectualProperty Office, of a Korean patent application number 10-2019-0099141,filed on Aug. 13, 2019, in the Korean Intellectual Property Office, of aKorean patent application number 10-2019-0104680, filed on Aug. 26,2019, in the Korean Intellectual Property Office, of a Korean patentapplication number 10-2019-0127198, filed on Oct. 14, 2019 in the KoreanIntellectual Property Office, of a Korean patent application number10-2019-0134831, filed on Oct. 28, 2019, in the Korean IntellectualProperty Office, and of a Korean patent application number10-2020-0073931, filed on Jun. 17, 2020, in the Korean IntellectualProperty Office, the disclosures of each of which is incorporated byreference herein in its entirety.

BACKGROUND 1. Field

The disclosure relates to a method and apparatus for identifying a userand generating and transmitting an identifier by a base station (BS) ina wireless communication system.

2. Description of Related Art

Due to commercialization of a 5^(th)-generation (5G) communicationsystem (hereinafter, interchangeably used with a 5G system or a newradio or next radio (NR) system) to satisfy demand for radio datatraffic, services having a high data transmission rate are provided tousers through the 5G system along with a 4th-generation (4G) system, andit is predicted to provide IoT and wireless communication serviceshaving various purposes such as services that require high reliabilityfor a specific purpose.

In a system currently used with the 4G communication system and the 5Gcommunication system, an open radio access network (O-RAN) establishedby service providers and equipment provision companies defines a newnetwork element (NE) and an interface standard on the basis of theconventional 5GPP standard to create an O-RAN structure.

The above information is presented as background information only toassist with an understanding of the disclosure. No determination hasbeen made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the disclosure.

SUMMARY

According to the currently commercialized4^(th)-generation/5^(th)-generation communication systems (hereinafter,referred to as a 4G/5G system, new radio or next radio (NR)), supportingof differentiated service to a user in a virtualized network isrequired, but it is impossible to specify a user in cell-relatedinformation collected by a RAN or an O-RAN. A method to solve theproblem is proposed.

Aspects of the disclosure are to address at least the above-mentionedproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the disclosure is to providea method and apparatus for identifying a user and generating andtransmitting an identifier by a BS in a wireless communication system.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

In accordance with an aspect of the disclosure, a method of a first nodein a wireless communication system is provided. The method includesidentifying a unique identifier of a user equipment (UE), identifying aradio access network (RAN) UE identifier of the UE, and transmittinginformation related to a mapping relation between the RAN UE identifierand the unique identifier of the UE to a second node, based on theunique identifier of the UE.

The unique identifier of the UE may be identified based on firstinformation transmitted from the UE and second information transmittedfrom a network entity, and the information related to the mappingrelation between the RAN UE identifier and the unique identifier of theUE may include at least one of RAN UE identifier information configuredbased on the unique identifier of the UE and a pair of the RAN UEidentifier and the unique identifier of the UE.

The unique identifier of the UE may be a 5G-globally unique temporaryidentifier (5G-GUTI), the first information may be 5G systemarchitecture evolution (SAE)-temporary mobile subscriber identity(5G-S-TMSI), the network entity may be an access and mobility managementfunction (AMF), and the second information may be a globally unique AMFidentifier (GUAMI), or the unique identifier of the UE may be a globallyunique temporary identifier (GUTI), the first information may be anSAE-temporary mobile subscriber identity (S-TMSI), the network entitymay be a mobility management entity (MME), and the second informationmay be a globally unique MME identifier (GUMMEI).

Measurement information of the UE may be transmitted from the first nodeto the second node along with the information related to the mappingrelation between the RAN UE identifier and the unique identifier of theUE.

In accordance with another aspect of the disclosure, a method of asecond node in a wireless communication system is provided. The methodincludes receiving information related to a mapping relation between aradio access network (RAN) UE identifier and a unique identifier of theUE from a first node, identifying the unique identifier of the UE andthe RAN UE identifier, and processing information on the UE receivedfrom at least one of a third node and a fourth node, based on the RAN UEidentifier of the UE.

The information related to the mapping relation between the RAN UEidentifier and the unique identifier of the UE may include at least oneof RAN UE identifier information configured based on the uniqueidentifier of the UE and a pair of the RAN UE identifier and the uniqueidentifier of the UE, and the unique identifier of the UE may be a5G-globally unique temporary identifier (5G-GUTI) or a globally uniquetemporary identifier (GUTI).

Measurement information of the UE may be transmitted from the first nodeto the second node along with the information related to the mappingrelation between the RAN UE identifier and the unique identifier of theUE. The second node may receive the RAN UE identifier andmeasurement-related information of the UE from at least one of the thirdnode and the fourth node and transmit information on the UE receivedfrom at least one of the first node, the third node, and the fourth nodeto a fifth node, and the information on the UE may be transmitted alongwith the unique identifier of the UE.

In accordance with another aspect of the disclosure, an apparatus forcontrolling a first node in a wireless communication system is provided.The apparatus includes a communication unit, and a controller configuredto perform control to identify a unique identifier of a UE and identifya radio access network (RAN) UE identifier of the UE, and connected tothe communication unit configured to perform control to transmitinformation related to a mapping relation between the RAN UE identifierand the unique identifier of the UE to a second node, based on theunique identifier of the UE.

In accordance with another aspect of the disclosure, an apparatus forcontrolling a second node in a wireless communication system isprovided. The apparatus includes a communication unit, and a controllerconfigured to receive information related to a mapping relation betweena radio access network (RAN) UE identifier and a unique identifier ofthe UE from a first node and identify the unique identifier of the UEand the RAN UE identifier, and connected to the communication unitconfigured to perform control to process information on the UE receivedfrom at least one of a third node and a fourth node, based on the RAN UEidentifier of the UE.

The disclosure can efficiently provide user-specific service oruser-demanded service through radio resource monitoring for a specificuser.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A illustrates an example of a 4G long term evolution (LTE) coresystem according to an embodiment of the disclosure;

FIG. 1B illustrates an example of a 3GPP 5G non-standard alone (NSA)system according to an embodiment of the disclosure;

FIG. 2 illustrates a configuration of an IMSI that is a uniqueidentifier of a UE used in common in 3^(rd) generation (3G), 4G, and 5Gsystems defined in International TelecommunicationUnion-Telecommunication Standardizaton Sector (ITU-T) according to anembodiment of the disclosure;

FIG. 3 illustrates a configuration of a GUTI used by an MME of an LTEcore network defined in a 3GPP standard according to an embodiment ofthe disclosure;

FIG. 4 illustrates an example of a 5G NR core system according to anembodiment of the disclosure;

FIG. 5 illustrates a configuration of a 5G-GUTI used in a 5G core systemaccording to an embodiment of the disclosure;

FIG. 6 illustrates an example of an O-RAN network system according to anembodiment of the disclosure;

FIG. 7 illustrates an example of connections between an O-RANintelligent controller (RIC) and a plurality of nodes such as anO-CU-CP, an O-CU-UP, and an O-DU according to an embodiment of thedisclosure;

FIG. 8 illustrates a procedure in which a CU-CP of a 5G RAN defined in a3GPP acquires a 5G-GUTI according to an embodiment of the disclosure;

FIG. 9 illustrates a procedure in which an O-CU-CP of a 5G RAN definedin an O-RAN acquires a 5G-GUTI according to an embodiment of thedisclosure;

FIG. 10 illustrates a procedure in which an evolved node B (eNB) of a 4GRAN defined in a 3GPP acquires a GUTI according to an embodiment of thedisclosure;

FIG. 11 illustrates a procedure in which an eNB of a 4G O-RAN defined inan O-RAN acquires a GUTI according to an embodiment of the disclosure;

FIG. 12 illustrates a procedure in which an eNB of a 4G RAN defined in a3GPP acquires a GUTI according to an embodiment of the disclosure;

FIG. 13 illustrates a procedure in which a CU-CP of a 5G RAN defined ina 3GPP acquires a 5G-GUTI according to an embodiment of the disclosure;

FIG. 14 illustrates a procedure in which a RIC defined in an O-RANreceives information classified for a specific UE from an O-DU and anO-CU-CP according to an embodiment of the disclosure;

FIG. 15 illustrates a procedure in which an NRT-RIC defined in an O-RANreceives information classified for a specific UE from an O-DU, anO-CU-CP, and a RIC according to an embodiment of the disclosure;

FIG. 16 illustrates a procedure in which a collection server receivesinformation classified for a specific UE from a DU, a CU-UP, and a CU-CPdefined in a 3GPP according to an embodiment of the disclosure;

FIG. 17 illustrates a procedure in which a RIC receives informationclassified for a specific UE from an O-DU, an O-CU-UP, an O-CU-CPdefined in an O-RAN according to an embodiment of the disclosure;

FIG. 18 illustrates an example of using a UE identifier based on a5G-GUTI proposed by the disclosure is used in an O-RAN according to anembodiment of the disclosure;

FIG. 19 illustrates a device for implementing the disclosure accordingto an embodiment of the disclosure;

FIG. 20 illustrates an example of a 5G non-standard alone (NSA) systemdefined in an O-RAN according to an embodiment of the disclosure;

FIG. 21 illustrates a procedure in which an eNB to which a UE makes callaccess acquires a GUTI in the case of NSA EN-DC defined in an O-RANaccording to an embodiment of the disclosure;

FIG. 22 illustrates a procedure in which a CU-CP of a 5G RAN defined ina 3GPP acquires a GUAMI when a UE performs initial attach according toan embodiment of the disclosure;

FIG. 23 illustrates a procedure in which an eNB of a 4G RAN defined in a3GPP acquires a GUMMEI when a UE performs initial attach according to anembodiment of the disclosure;

FIG. 24 illustrates an example of a procedure in which an O-CU-CP of a5G RAN defined in an O-RAN allocates a globally unique RAN UE ID in acore network when a UE performs initial attach according to anembodiment of the disclosure;

FIG. 25 illustrates a procedure in which an eNB in LTE/NSA defined in anO-RAN allocates a globally unique RAN UE ID in a core network when a UEperforms initial attach according to an embodiment of the disclosure;

FIG. 26 illustrates an example of a procedure in which an O-CU-CP of a5G RAN defined in the O-RAN allocates a RAN UE NGAP ID used for NGAPconfiguration with the core network as a RAN UE ID when a UE performsinitial attach according to an embodiment of the disclosure;

FIG. 27 illustrates a RAN UE NGAP ID specified in a 3GPP standardaccording to an embodiment of the disclosure;

FIG. 28 illustrates an example of a procedure in which an O-CU-CP of a5G RAN defined in an O-RAN allocates an AMF UE NGAP ID used for NGAPconfiguration with a core network as a RAN UE ID when a UE performsinitial attach according to an embodiment of the disclosure;

FIG. 29 illustrates a detailed configuration of an AMF UE NGAP IDaccording to an embodiment of the disclosure;

FIG. 30 illustrates a configuration of an MME UE S1AP ID according to anembodiment of the disclosure;

FIG. 31 illustrates an example of generating a UE identifier of 64 bitsthrough a hash function according to an embodiment of the disclosure;

FIG. 32 illustrates an example in which an NRT-RIC manages informationrelated to a UE-ID for each RFSP group according to an embodiment of thedisclosure;

FIG. 33 illustrates an example in which an NRT-RIC manages informationrelated to a UE-ID for each SPID group according to an embodiment of thedisclosure;

FIG. 34 illustrates another example in which an NRT-RIC managesinformation related to a UE-ID for each RFSP group according to anembodiment of the disclosure;

FIG. 35 illustrates another example in which an NRT-RIC managesinformation related to a UE-ID for each SPID group according to anembodiment of the disclosure;

FIG. 36 illustrates a RIC UE ID registry stored by a RIC proposed by thedisclosure according to an embodiment of the disclosure;

FIG. 37 illustrates an NRT-RIC UE ID registry stored by an NRT-RICaccording to an embodiment of the disclosure; and

FIG. 38 illustrates a method by which a RIC generates a Secure Hashed5G-GUTI/Secure Hashed GUTI according to an embodiment of the disclosure.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components, and structures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thedisclosure. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of thedisclosure. Accordingly, it should be apparent to those skilled in theart the following description of various embodiments of the disclosureis provided for illustration purpose only and not for the purpose oflimiting the disclosure as defined by the appended claims and theirequivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

The advantages and features of the disclosure and ways to achieve themwill be apparent by making reference to embodiments as described belowin detail in conjunction with the accompanying drawings. However, thedisclosure is not limited to the embodiments set forth below, but may beimplemented in various different forms. The following embodiments areprovided only to completely disclose the disclosure and inform thoseskilled in the art of the scope of the disclosure, and the disclosure isdefined only by the scope of the appended claims. Throughout thespecification, the same or like reference numerals designate the same orlike elements.

Here, it will be understood that each block of the flowchartillustrations, and combinations of blocks in the flowchartillustrations, can be implemented by computer program instructions.These computer program instructions can be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions specified in the flowchart block or blocks.These computer program instructions may also be stored in a computerusable or computer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer usable orcomputer-readable memory produce an article of manufacture includinginstruction means that implement the function specified in the flowchartblock or blocks. The computer program instructions may also be loadedonto a computer or other programmable data processing apparatus to causea series of operations to be performed on the computer or otherprogrammable apparatus to produce a computer implemented process suchthat the instructions that execute on the computer or other programmableapparatus provide operations for implementing the functions specified inthe flowchart block or blocks.

Further, each block of the flowchart illustrations may represent amodule, segment, or portion of code, which includes one or moreexecutable instructions for implementing the specified logicalfunction(s). It should also be noted that in some alternativeimplementations, the functions noted in the blocks may occur out of theorder. For example, two blocks shown in succession may in fact beexecuted substantially concurrently or the blocks may sometimes beexecuted in the reverse order, depending upon the functionalityinvolved.

As used herein, the “unit” refers to a software element or a hardwareelement, such as a Field Programmable Gate Array (FPGA) or anApplication Specific Integrated Circuit (ASIC), which performs apredetermined function. However, the “unit” does not always have ameaning limited to software or hardware. The “unit” may be constructedeither to be stored in an addressable storage medium or to execute oneor more processors. Therefore, the “unit” includes, for example,software elements, object-oriented software elements, class elements ortask elements, processes, functions, properties, procedures,sub-routines, segments of a program code, drivers, firmware,micro-codes, circuits, data, database, data structures, tables, arrays,and parameters. The elements and functions provided by the “unit” may beeither combined into a smaller number of elements, or a “unit”, ordivided into a larger number of elements, or a “unit”. Moreover, theelements and “units” or may be implemented to reproduce one or more CPUswithin a device or a security multimedia card.

In the disclosure, an uplink is a radio link through which a terminal (auser equipment (UE) or a mobile station (MS)) transmits data or acontrol signal to a base station (BS) (or an eNode B), and a downlink isa radio link through which the BS transmits data or a control signal tothe terminal. The BS is the entity that allocates resources to the UE,and may be one of an eNode B, a Node B, a Base Station (BS), ageneration Node B (gNB), a radio access unit, a base station controller,and a node on a network. The terminal may include a user equipment (UE),a mobile station (MS), a cellular phone, a smailphone, a computer, or amultimedia system capable of performing a communication function.

Due to commercialization of a 5-generation communication system(hereinafter, interchangeably used with a 5G system or a new radio ornext radio (NR) system to satisfy demand for radio data traffic,services having a high data transmission rate are provided to usersthrough the 5G system along with a 4G system, and providing IoT andwireless communication services having various purposes such as servicesthat require high reliability for a specific purpose is predicted.

In a system currently used with the 4G communication system and the 5Gcommunication system, an open radio access network (O-RAN) establishedby service providers and equipment provision companies defines a newnetwork element (NE) and an interface standard on the basis of theconventional 5GPP standard to create an O-RAN structure. The O-RAN newlydefines the conventional 3GPP NE, RU, DU, CU-CP, and CU-UP as O-RU,O-DU, O-CU-CP, and O-CU-UP, respectively (integrated into an O-RAN BS)and additionally standardizes a near-real-time RAN intelligentcontroller (RIC) and a non-real-time RAN intelligent controller(NRT-RIC). The newly defined RIC is a logical node that may beintensively arrange servers in one physical place and may collectinformation on a cell site transmitted and received by the actualterminal and the O-DU, the O-CU-CP, and the O-CU-UP (O-RAN BS). The O-DUand the RIC may be connected through Ethernet, the O-CU-CP and the RICmay be connected through Ethernet, and the O-CU-UP and the RIC may beconnected through Ethernet. Further, interface standards forcommunication between the O-DU and the RIC, between the O-CU-CP and theRIC, and between the O-CU-UP and the RIC are needed, and the standardsE2-DU, E2-CU-CP, and E2-CU-UP are currently used between the RIC and theO-CU, the O-CU-CP, and the O-CU-UP, respectively.

According to the current commercialization of a4^(th)-generation/5^(th)-generation communication system (hereinafter,referred to as a 4G/5G system, new radio or next radio (NR)), supportingof differentiated service to a user in a virtualized network isrequired, but it is impossible to specify a user for cell-relatedinformation collected by a RAN or an O-RAN. The reason is there is anidentifier of a UE (hereinafter, referred to as a RAN UE identifier)used by an O-DU, an O-CU-CP, and an O-CU-UP in a radio access network(RAN) according to the 3GPP standard, but (unique) information on a user(or information for specifying a user, a user identifier, or a useridentity, for example, an international mobile subscriber identity(IMSI), a subscription permanent identifier (SUPI), or a subscriptionconcealed identifier (SUCI)) cannot be known.

Specifically, when the RIC receives UE-specific measurement informationand call-related information based on the RAN UE identifier from theO-DU, the O-CU-CP, and the O-CU-UP, a plurality of O-CU-CPs may beconnected to the RIC, and thus RAN UE identifiers may overlap and, whenthe O-CU-CP connected to the UE is changed, the RAN UE identifier may bechanged. Accordingly, based on the 3GPP standard, in order to specify auser to indicate a user for which information is collected by the RAN orthe O-RAN, the RAN and the core network may identify the user, and auser identifier (ID) (interchangeably used with a user identity, a UEidentifier, or a UE identity) which can be used by the RAN is needed.

The RIC and/or the NRT-RIC may identify that information collected bythe RAN or the O-RAN is for a specific user on the basis of the useridentifier. The collected information may be transmitted from at leastone of the (O-)CU-CP, the (O-)CU-UP, and the (O-)DU, and the collectionserver, the RIC and/or the NRT-RIC may identify that informationcollected from different entities is for one specific user on the basisof the user identifier, and determine a key performance indicator (KPI)of service provided to each user on the basis of the collectedinformation.

Since it could not be identified previously that the collectedinformation is for a specific user, radio resource monitoring for eachuser was not possible. However, it is possible to optimize resources fora user and efficiently provide user-specific service or user-demandedservice through radio resource monitoring for the specific user in thedisclosure. For example, the RIC (NRT-RIC or collection server) mayefficiently truncate network slices or configure an additional carrierto allow a specific UE to receive service through carrier aggregation inorder to optimize resources, or may configure an additional cell fordual connectivity to allow the specific UE to receive service throughdual connectivity. Further, the RIC (NRT-RIC or collection server) mayconfigure the specific UE to avoid a connection with a specific cellduring movement between cells and to be connected to the specific cell.In addition, the RIC (NRT-RIC or collection server) may efficientlyoptimize resources through machine learning through analysis based onthe collected information. Resource optimization according to thedisclosure is not limited to the description. Further, according to thedisclosure, it is possible to not only collect information for each UEbut also collect information for each bearer.

Further, the collected information on the specific user may be used bythe collection server, the RIC, or the NRT-RIC, and may be provided toan operations support system (OSS) and/or a business support system(BSS) and used to provide specialized service to the user.

FIG. 1A illustrates a 4G LTE core system according to an embodiment ofthe disclosure.

Referring to FIG. 1A, an evolved node B (eNB) 100 that is a 4G BS isconnected to a mobile management entity (MME) 120 of the 4G core systemthrough an S1-MME interface. The eNB is a device that collects stateinformation such as a buffer state of a UE 110, available transmissionpower, and a channel state to perform scheduling. The MME performs afunction of managing mobility of the UE and performing various controls.A serving gateway 130 provides a data bearer and generates or controlsthe data bearer according to the control of the MME. The MME is capableof internally identifying the UE with a globally unique temporaryidentifier (GUTI).

A carrier aggregation (GA) technology is a technology for aggregating aplurality of component carriers and allowing one UE to simultaneouslyuse the plurality of component carriers to transmit and receive asignal, thereby increasing frequency usage efficiency in a viewpoint ofthe UE or the BS. Specifically, according to the CA technology, the UEand the BS may transmit and receive a signal through a broadband using aplurality of component carriers in each of an uplink (UL) and a downlink(DL), in which case the respective component carriers are located indifferent frequency bands. Hereinafter, the uplink is a communicationlink through which the UE transmits a signal to the BS, and the downlinkis a communication link through which the BS transmits a signal to theUE. At this time, the number of uplink component carriers and the numberof downlink component carriers may be different from each other.

A dual connectivity/multi connectivity technology is a technology inwhich one UE is connected to a plurality of different BSs and transmitsand receives signals simultaneously using carriers within the pluralityof BSs located in different frequency bands, thereby increasingfrequency usage efficiency in a viewpoint of the UE or the BS. The UEmay be simultaneously connected to a first BS (for example, a BSproviding service using a long term evolution (LTE) technology or a4^(th)-generation mobile communication technology) and a second BS (forexample, a BS providing service using a new radio (NR) technology or a5^(th)-generation mobile communication technology) to transmit andreceive traffic, in which case frequency resources used by the BSs maybe located in different bands. As described above, a scheme foroperation based on dual connectivity of LTE and NR may be referred to as5G non-standalone (5G NSA).

FIG. 1B illustrates an example of a 5G NAS system according to anembodiment of the disclosure.

Referring to FIG. 1B, the 5G NSA system may include an EPC 150 LTE 160(or interchangeably used with an LTE BS or an eNB), NR 170 (orinterchangeably used with an NR BS or a gNB), and a UE 180. The LTE BS160 and the NR BS 170 may be connected to the EPC 150, and the UE 180may simultaneously receive services from the LTE 160 and the NR 170.

In this case, the UE may perform RRC connection through the first BS,receive a function (for example, a connection management or mobilitymanagement function) provided in a control plane, and receive additionalradio resources for transmitting and receiving data through the secondBS. The dual connectivity technology may be referred to as evolveduniversal terrestrial radio access (EN-DC)-NR dual connectivity. Thedisclosure is not limited to the EN-DC, and may be applied to NR-E-UTRAdual connectivity (NE-DC) through which the first BS uses NR and thesecond BS uses LTE and to any multi connectivity in various forms.Further, the disclosure may be applied to carrier aggregation.

In addition, the disclosure may be applied to the case in which a firstsystem using a first communication technology and a second system usinga second communication technology are implemented in one device or thecase in which the first BS and the second BS are located at the samegeographical place.

FIG. 2 illustrates international mobile subscription identity (IMSI)that is a unique identifier of the UE used in common by all of 3G, 4G,and 5G systems defined in ITU-T according to an embodiment of thedisclosure.

Referring to FIG. 2 , the UE may be uniquely identified through the IMSI200 around the globe. The IMSI includes a mobile country code (MCC) 210,a mobile network code (MNC) 220, and a mobile subscriber identificationnumber (MSIN) 230. The MCC is an identifier for identifying a countryall over the world, and the MNC is an identifier for identifying apublic land mobile network (PLMN) (interchangeably used with anoperator). The MSIN is an identifier for identifying a UE within thePLMN.

FIG. 3 illustrates a GUTI used in a 4G LTE core system according to anembodiment of the disclosure.

Referring to FIG. 3 , a GUTI 300 is an identifier for identifying aspecific UE in a core network (interchangeably used with a network)including a plurality of MMEs. The GUTI includes a globally unique MMEidentifier (GUMMEI) 310 and an M-temporary mobile subscriptionidentifier (TMSI) 320. The GUMMEI includes an MCC 330, an MNC 340, andan MME identifier 350. The MME identifier includes an MME group ID 360and an MME code 370. The MME group ID indicates an MME group including aplurality of MMEs, and the MME code indicates a specific MME. The M-TMSI320 is an MME-TMSI, and may uniquely identify a UE only within the MME.An SAE-temporary mobile subscriber identity (S-TMSI) 380 may begenerated through a combination of the MME code and the M-TMSI, and is atemporary UE identifier by which the MME identifies a user within theMME group.

FIG. 4 illustrates a 5G NR core system according to an embodiment of thedisclosure.

Referring to FIG. 4 , a 5G core system 460 may include network functionssuch as an access and mobility management function (AMF) 430, a sessionmanagement function (SMF) 440, and a user plane function (UPF) 450. TheAMF provides a function of access in units of UEs 420 and mobilitymanagement, which may be similar to the role of the MME of the LTE corenetwork. The SMF provides a session management function, and the UPFtransfers downlink data received from a data network (not shown) to theUE via a gNB 400, and transfers uplink data received from the UE to thedata network via the gNB.

The 5G BS (generation node B (gNB)) 400 may be logically divided into aradio unit (RU) 410 performing a physical layer function, a digital unit(DU) 402 performing a medium access control (MAC) and radio link control(RLC) function, a central unit-control plane (CU-CP) 404 performing ahigher-layer function such as radio resource control (RRC) and packetdata convergence protocol (PDCP), and a central unit-user plane (CU-UP)function 406. The CU-CP performs a function related to a control plane,and specifically may perform a function related to connection setup,mobility, and security. The CU-UP may perform a user datatransmission/reception-related function as a function related to a userplane. The gNB is connected to the AMF, and a plurality of AMFs of the5G core network exists in a service provider network.

FIG. 5 illustrates the structure of a 5G-globally unique temporaryidentifier (5G-GUTI) used in the 5G core system according to anembodiment of the disclosure.

Referring to FIG. 5 , a 5G-GUTI 500 is an identifier for identifying aspecific UE in the 5G core network including a plurality of AMFs, andthe 5G-GUTI includes a globally unique AMF identifier (GUAMI) 510 and a5G-temporary mobile subscription identifier (5G-TMSI) 520. The GUAMIincludes an MCC 530, an MNC 540, and an AMF identifier 560. The AMFidentifier includes an AMF region ID 560, an AMF set ID 570, and an AMFpointer 580. The AMF region ID indicates a an AMF set including aplurality of AMFs, the AMF set ID indicates a specific AMF set within anAMF region, and the AMF pointer indicates a specific AMF within the AMFset. The 5G-TMSI is an identifier for uniquely identifying a UE only inthe AMF pointer. A 5G SAE-temporary mobile subscription identity(5G-S-TMSI) 590 may include a combination of an AMF set ID, an AMFpointer, and a 5G-TMSI, and may be used to more efficiently performwireless signaling in a short form of the 5G-GUTI.

FIG. 6 illustrates an O-RAN network system according to an embodiment ofthe disclosure.

Referring to FIG. 6 , the O-RAN network is a standard that logicallyseparates eNB and gNB functions of conventional 4G and 5G, and anon-real time RAN intelligent controller (NRT-RIC) 600, a near-real-time(RIC) RAN intelligent controller 610, an O-CU-CP 620, an O-CU-UP 630,and an O-DU 640 are newly defined in the O-RAN standard. The O-CUincluding the O-CU-CP and the O-CU-UP is a logical node providingfunctions of RRC, a service data adaptation protocol (SDAP), and a PDCP,the O-CU-CP is a logical node providing functions of the control planepart of RRC and the PDCP, the O-CU-UP is a logical node providingfunctions of the user plane part of the SDAP and the PDCP, the O-DU is alogical node providing functions of RLC, MAC, and a higher physicallayer (high-PHY based on 7-2× fronthaul split), and an O-RU connected toan O-DU which is not illustrated is a logical node providing functionsof a lower physical layer (low-PHY based on 7-2× fronthaul split) and RFprocessing.

The NRT-RIC is a logical node allowing non-real-time control rather thanreal-time control, optimization of RAN elements and resources, modeltraining, and update, and the RIC is a logical node allowingnear-real-time control and optimization of RAN elements and resources onthe basis of data collected from the O-DU, the O-CU-CP, and the O-CU-UPthrough an E2 interface.

The disclosure is not limited by a name of each node described above,and the configuration of the disclosure may be applied to the logicalnodes or entities performing the functions described above. The logicalnodes may be located in physically the same place or different places,and functions thereof may be provided by the same physical device (forexample, a processor or a controller) or by different physical devices.For example, one physical device may provide the function of at leastone logical node through virtualization.

FIG. 7 illustrates an example of the connection between a plurality ofnodes such as the O-RAN RIC and the O-CU-CP, the O-CU-UP, and the O-DUaccording to an embodiment of the disclosure.

Referring to FIG. 7 , one RIC 700 may be connected to a plurality ofnodes such as an O-CU-CP 720, an O-CU-UP 710, and an O-DU 730, and maybe connected to the respective nodes through an E2-CP interface 750, anE2-UP interface 760, and an E2-DU interface 740. Further, an interfacebetween the O-CU-CP and the DU and between the O-CU-UP and the DU may bereferred to as an F1 interface 770. Hereinafter, the DU may beinterchangeably used with the O-DU, the CU-CP may be interchangeablyused with the O-CU-CP, and the CU-UP may be interchangeably used withthe O-CU-UP. Further, the eNB may be interchangeably used with an O-RANeNB, and the gNB may be interchangeably used with an O-RAN gNB. AlthoughFIG. 7 illustrates only one RIC 700, a plurality of RICs may exist,which may be implemented as a plurality of pieces of hardware located inthe same physical place or implemented through virtualization using onepiece of hardware.

FIG. 8 illustrates a procedure in which a CU-CP of a 5G RAN defined inthe 3GPP acquires a 5G-GUTI according to an embodiment of thedisclosure.

Referring to FIG. 8 , in operation 800, a UE 801 inserts upper 39 bitsof a 5G SAE temporary mobile subscriber identity (5G-S-TMSI) valueallocated by the 5G core network in initial setup into anRRCSetupRequest message and transmits the RRCSetupRequest message to aDU 802 according to a call access procedure defined in the 3GPPstandard. In operation 810, the DU 802 inserts the upper 39 bits of the5G-S-TMSI value received in operation 800 into an F1 initial UL RRCmessage transfer message and transmits the F1 initial UL RRC messagetransfer message to a CU-CP 804 according to the call access proceduredefined in the 3GPP standard. In operation 820, the CU-CP 804 stores theupper 39 bits of the 5G-S-TMSI value, which was inserted into the F1message and transmitted by the DU 802. Thereafter, the CU-CP transfers aDL RRC message to the DU 802, and the DU transmits an RRCSetup message(or an RRCReject message) to the UE 801.

When the DU 802 transmits the RRCSetup message, the UE 801 inserts lower9 bits of the 5G-S-TMSI value allocated by the core network in theinitial setup into an RRCSetupComplete message and transmits theRRCSetupComplete message to the DU according to the call accessprocedure defined in the 3GPP standard in operation 830. In operation840, the DU 802 inserts the lower 9 bits of the 5G-S-TMSI value receivedin the fourth procedure into an F1 UL RRC message transfer message andtransmits the F1 UL RRC message transfer message to the CU-CP 804according to the call access procedure defined in the 3GPP standard. Inoperation 850, the CU-CP 804 stores the lower 9 bits of the 5G-S-TMSIvalue, which was inserted into the F1 message and transmitted by the DU802. Thereafter, the CU-CP transmits an initial UE message to an AMF805.

In operation 860, the CU-CP 804 stores a GUAMI value, which is insertedinto a NGAP INITIAL CONTEXT SETUP REQUEST message and transmitted by theAMF 805, according to the call access procedure defined in the 3GPPstandard. In operation 870, the CU-CP 804 identifies the 5G-TMSI on thebasis of the upper 39 bits and the lower 9 bits of the 5G-S-TMSI storedin operation 820 and operation 850 and generates a 5G-GUTI byconcatenating the 5G-TMSI with a lower part of the GUAMI received inoperation 860.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 8 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 8 .

FIG. 9 illustrates a procedure in which an O-CU-CP of a 5G RAN definedin the O-RAN acquires a 5G-GUTI according to an embodiment of thedisclosure.

Referring to FIG. 9 , in operation 900, a UE 901 inserts upper 39 bitsof a 5G-S-TMSI value allocated by the core network into anRRCSetupRequest message and transmits the RRCSetupRequest message to anO-DU 902 in initial setup according to a call access procedure definedin the 3G PP standard. In operation 910, the O-DU inserts the upper 39bits of the 5G-S-TMSI value received in operation 900 into an F1 initialUL RRC message transfer message and transmits the F1 initial UL RRCmessage transfer message to an O-CU-CP 904 according to the call accessprocedure defined in the 3GPP standard. In operation 920, the O-CU-CP904 stores the upper 39 bits of the 5G-S-TMSI value, which was insertedinto the F1 message and transmitted by the O-DU 902. Thereafter, theO-CU-CP 904 transfers a DL RRC message to the O-DU 902, and the O-DU 902transmits an RRCSetup message (or an RRCReject message) to the UE 901.

When the O-DU 902 transmits the RRCSetup message, the UE 901 insertslower 9 bits of the 5G-S-TMSI value allocated by the core network in theinitial setup into an RRCSetupComplete message and transmits theRRCSetupComplete message to the O-DU 902 according to the call accessprocedure defined in the 3GPP standard in operation 930. In operation940, the O-DU 902 inserts the lower 9 bits of the 5G-S-TMSI valuereceived in the fourth procedure into an F1 UL RRC message transfermessage and transmits the F1 UL RRC message transfer message to theO-CU-CP 904 according to the call access procedure defined in the 3GPPstandard. In operation 950, the O-CU-CP 904 stores the lower 9 bits ofthe 5G-S-TMSI value, which was inserted into the F1 message andtransmitted by the O-DU 902.

Thereafter, the O-CU-CP transmits an initial UE message to an AMF 905,and stores a GUAMI value, which is inserted into a NGAP INITIAL CONTEXTSETUP REQUEST message and transmitted by the AMF 905, according to thecall access procedure defined in the 3GPP standard in operation 960. Inoperation 970, the O-CU-CP identifies the 5G-TMSI on the basis of theupper 39 bits and the lower 9 bits of the 5G-S-TMSI stored in operation920 and operation 950 and generates a 5G-GUTI by concatenating the5G-TMSI with a lower part of the GUAMI received in operation 960.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 9 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 9 .

FIG. 10 illustrates a procedure in which an eNB of a 4G RAN defined inthe 3GPP acquires a GUTI according to an embodiment of the disclosure.

Referring to FIG. 10 , in operation 1000, a UE 1001 inserts 40 bits ofan S-TMSI value allocated by the core network into an RRC connectionrequest message and transmits the RRC connection request message to aneNB 1002 in initial setup according to a call access procedure definedin the 3GPP standard. In operation 1010, the eNB 1002 stores the S-TMSIvalue transmitted by the UE 1001. Thereafter, the eNB 1002 transmits anRRCConnectionSetup message to the UE 1001, and the UE 1001 transmitsRRCConnectionSetupComplete message to the eNB 1002 in response thereto.Thereafter, the eNB 1002 transmits an initial UE message to an MME 1003.In operation 1020, the eNB 1002 stores a GUMMEI value, which is insertedinto an S1AP INITIAL CONTEXT SETUP REQUEST message and transmitted bythe MME 1003, according to the call access procedure defined in the 3GPPstandard. In operation 1030, the eNB 1002 identifies an MME temporarymobile subscriber identity (M-TMSI) on the basis of the S-TMSI stored inoperation 1010 and generates a GUTI by concatenating the M-TMSI with alower part of the GUMMEI received in operation 1020.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 10 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 10 .

FIG. 11 illustrates a procedure in which an eNB of a 4G O-RAN defined inthe O-RAN acquires a GUTI according to an embodiment of the disclosure.

Referring to FIG. 11 , in operation 1100, a UE 1101 inserts 40 bits ofan S-TMSI value allocated by the core network into an RRC ConnectionRequest message and transmits the RRC Connection Request message to aneNB 1102 of the O-RAN in initial setup according to the call accessprocedure defined in the 3GPP standard. In operation 1110, the eNB 1102stores the S-TMSI value transmitted by the UE 1101. Thereafter, the eNB1102 transmits an RRCConnectionSetup message to the UE 1101, and the UE1101 transmits RRCConnectionSetupComplete message to the eNB 1102 inresponse thereto. Thereafter, the eNB 1102 transmits an initial UEmessage to an MME 1103. In operation 1120, the eNB 1102 of the O-RANstores a GUMMEI value, which is inserted into an S1AP INITIAL CONTEXTSETUP REQUEST message and transmitted by the MME 1103, according to thecall access procedure defined in the 3GPP standard. In operation 1130,the eNB 1102 of the O-RAN identifies an M-TMSI on the basis of theS-TMSI stored in operation 1110 and generates a GUTI by concatenatingthe GUMMEI received in operation 1120 with a lower part of the M-TMSI.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 11 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 11 .

FIG. 12 illustrates the configuration in which an eNB of a 4G RANdefined in the 3GPP generates a GUTI on the basis of an S-TMSI receivedfrom a UE and a GUMMEI received from an MME according to an embodimentof the disclosure.

Referring to FIG. 12 , the eNB identifies an M-TMSI 1220 by applying amask of lower 32 bits to an S-TMSI 1200. The eNB generates a GUTI 1230by concatenating a GUMMEI 1210 before the M-TMSI 1220. At this time, amethod of generating the GUTI 1230 is not limited to the masking, andthe GUTI 1230 may be generated through various methods based on anS-TMSI 1200 and a GUMMEI 1210.

FIG. 13 illustrates the configuration in which a CU-CP of a 5G RANdefined in the 3GPP generates a 5G-GUTI on the basis of a 5G-S-TMSIreceived from a UE and a GUAMI received from an AMF according to anembodiment of the disclosure.

Referring to FIG. 13 , the CU-CP identifies a 5G-TMSI 1320 by applying amask of lower 32 bits to a 5G-S-TMSI 1300. The CU-CP generates a 5G-GUTI1330 by concatenating a GUAMI 1310 before the 5G-TMSI. At this time, amethod of generating the 5G-GUTI 1330 is not limited to the masking, andthe GUTI may be generated through various methods based on a 5G-S-TMSI1300 and a GUAMI 1310.

FIG. 14 illustrates a procedure in which a RIC defined in the O-RANreceives information classified for a specific UE from an O-DU and anO-CU-CP according to an embodiment of the disclosure.

Referring to FIG. 14 , in operation 1400, an O-CU-CP 1402 generates a5G-GUTI by communicating with a UE and an AMF. The 5G-GUTI may begenerated through the above-described method. In operation 1410, the RIC1403 transmits an E2-CP RIC SUBSCRIPTION REQUEST message defined in theO-RAN standard to the O-CU-CP 1402 and transmits a report classified fora specific UE when a specific event is generated. In operation 1420, theO-CU-CP 1402 processes a request configured in operation 1410 to the RIC1403, and inserts a RAN UE ID defined in the 3GPP and the 5G-GUTIconfigured in operation 1400 mapped to the RAN UE ID into an E2 E2-CPRIC SUBSCRIPTION RESPONSE message and transmits the E2-CP RICSUBSCRIPTION RESPONSE message to the RIC 1403.

The RIC 1403 may identify a UE for which the information is collected(that is, a 5G-GUTI which the UE has) on the basis of a mapping relationbetween the RNA UE ID and the 5G-GUTI. A detailed description thereofwill be described below.

RAN UE ID is a temporary UE identifier defined in the 3GPP, andcorresponds to a UE identifier used between a CU-CP, a CU-UP, and a DU.This may be configured between nodes in F1 interface setup, is used toidentify a specific UE between nodes and report call-related informationand measurement-related information to the specific UE, and is definedto have 64 bits. The RAN UE ID is a temporarily determined UE identifierwithin an O-RAN BS, and may be configured as operation administrationmaintenance (OAM) by a service provider. For a specific example, the RANUE ID may be used to report call summary log (CSL) information to a calllog collection server. The O-CU-CP 1402 may configure the RAN UE ID inany way. For example, the RAN UE ID may be included in a UE contextsetup request message and a UE context setup response messagetransmitted and received between the DU and the CU, and may be includedin a bearer context modification request message and a bearer contextmodification failure message transmitted and received between the CU-CPand the CU-UP. In another example, the RAN UE ID may be included in ahandover request message and a handover request acknowledge messagetransmitted and received by a source gNB and a target gNB, may beincluded in a retrieve UE context request message and a retrieve UEcontext response message of an old gNB and a new gNB, may be included ina handover required message and a handover command message between asource gNB and an AMF, may be included in an S-node addition requestmessage and an S-node request acknowledge message between a master gNBand a second gNB, may be included in an initial UE message transmittedto an AMF by a gNB, and may be included in a handover request messageand a handover request acknowledge message between a target gNB and anAMF.

The disclosure describes an example in which the RAN UE ID and the 5GGUTI are inserted into the E2-CP RIC SUBSCRIPTION RESPONSE message andtransmitted, the O-CU-CP 1402 may configure the RAN UE ID on the basisof a combination of the 5G-GUTI and a value for uniquely identifying aUE shared with the core network or a combination of the GUAMI and avalue for identifying a UE shared with the core network. In the 5Gnetwork, user data management (UDM) stores a permanent ID of the user, asubscription permanent ID (SUPI), subscription data, and policy data,and the AMF stores mapping information between the SUPI and the 5G-GUTIor mapping information between the RAN UE ID, the 5G-GUTI, and the SUPI.The value for identifying the UE shared with the core network may bebased on the mapping information. The AMF may store mapping informationbetween the value for identifying the UE and an identifier for globallyand uniquely identifying a UE such as the 5G GUTI or the SUPI.

In this case, the RAN UE ID may be determined by a function (or a rule)having, as keys, one or more parameters including a 5G-GUTI (or acombination of the value for uniquely identifying the UE shared with thecore network or a GUAMI and a value for identifying the UE shared withthe core network, and hereinafter the 5G-GUTI may be understood as oneof combinations of the 5G-GUTI, the value for uniquely identifying theUE shared with the core network, or the GUAMI, and the value foridentifying the UE shared with the core network), and the function maybe predetermined or preconfigured. In this case, the RIC 1403 mayacquire a 5G-GUTI value of the specific UE according to thepredetermined or preconfigured function (or rule) on the basis of thereceived RAN UE ID of the specific UE. The O-CU-CP 1402 may transmitonly the RAN UE ID and/or the 5G-GUTI to the RIC 1403 or also transmit aparameter applied to generate the RAN UE ID from the 5G-GUTI in additionto the RAN UE ID and/or the 5G-GUTI. Alternatively, a maximum length ofthe currently defined RAN UE ID is 64 bits and a length of the 5G-GUTIis 62 bits, and thus the O-CU-CP 1402 may configure the content of theRNA UE ID to be the same as the 5G-GUTI. In the above-described case orwhen the value for identifying the UE shared with the core networkincluding the GUAMI is used as the RAN UE ID, the O-CU-CP 1402 maytransmit only the RAN UE ID to the RIC. The method is not limited to theexample of FIG. 14 and may be applied to entirety of the disclosure.

The O-CU-CP 1402 may transmit the RAN UE ID (and the 5G-GUTI) throughanother message other than the E2 E2-CP RIC SUBSCRIPTION RESPONSEmessage, and the disclosure may be applied to the case.

In operation 1430, the RIC transmits an E2-DU RIC SUBSCRIPTION REQUESTmessage defined in the O-RAN standard to the O-DU 1401 and, when aspecific event is generated, transmits a report classified for eachspecific UE. In operation 1440, the O-DU 1401 processes a request fromthe RIC 1403 in operation 1430, and inserts the RAN UE ID and the reportfor each RAN ID into an E2-DU RIC SUBSCRIPTION RESPONSE and transmitsthe E2-DU RIC SUBSCRIPTION RESPONSE to the RIC 1403. The report isUE-related information, and specifically is UE-related measurementinformation, and may include at least one piece of DU resource stateinformation, UE KPI-related information (including at least one piece ofthroughput and latency-related information). The report is not limitedto the example of FIG. 14 and may be applied to the entirety of thedisclosure.

When the preset event of operation 1410 is generated, the O-CU-CP 1402transmits information classified for each RAN UE ID to the RIC 1403through an E2-CP INDICATION message defined in the O-RAN in operation1460. The information may include one or more RAN UE IDs and informationfor each RAN UE ID. The information may pertain to at least one piece ofKPI-related information for each UE in the CU-CP and UE contextinformation and may be applied to the entirety of the disclosure withoutbeing limited to the example of FIG. 14 .

When the preset event of operation 1410 is generated, the O-DU 1401transmits information classified for each RAN UE ID to the RIC 1403through an E2-DU INDICATION message defined in the O-RAN in operation1460. The information may include one or more RAN UE IDs and informationfor each RAN UE ID.

The RIC 1403 identifies a 5G-GUTI associated with the RAN UE ID andstore information on each RAN UE ID transmitted by the O-CU-CP 1402 andthe O-DU 1401 in operations 1450 and 1460 to be associated with the5G-GUTI. That is, for one 5G-GUTI, information on a specific usertransmitted by each of the O-CU-CP 1402 and the O-DU 1401 may be stored.At this time, since a plurality of O-CU-CPs and a plurality of O-DUs maybe connected to the RIC 1403, RAN UE IDs transmitted by the O-CU-CP 1402and the O-DU 1401 may overlap each other. The RIC 1403 may identify the5G-GUTI on the basis of port information of the O-CU-CP 1402 and/or theO-DU 1401 transmitting the RAN UE ID (and information thereon) oridentify the 5G-GUTI on the basis of an RAN function ID and the RAN UEID of the O-CU-CP 1402 and/or the O-DU 1401.

The RAN UE ID is only an example of a specific user identifier of theO-RAN, and the specific user identifier (or UE identifier) of the O-RANmay be used in the disclosure. The 5G-GUTI is only an example of aglobally unique identifier of the UE (or user), and the globally uniqueidentifier of the UE (or user) may be used in the disclosure.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Another componentillustrated in FIG. 14 may be performed in addition to the describedproduce, and a procedure illustrated in another figure may be combinedwith the procedure illustrated in FIG. 14 . A name of the messageillustrated in FIG. 14 is only an example, and the configuration of thedisclosure may be applied to a method and message similar to those usedin the disclosure.

FIG. 15 illustrates a procedure in which an NRT-RIC defined in the O-RANreceives information classified for a specific UE from an O-DU, anO-CU-CP, and a RIC according to an embodiment of the disclosure.

Referring to FIG. 15 , an O-DU 1501, an O-CU-UP 1502, an O-CU-CP 1503,and a RIC 1504 transmit information on each UE identified by a RAN UE IDand information on each cell to a NRT-RIC 1505 through an O1 messagedefined in the O-RAN in operation 1500. The RIC 1504 also transmit5G-GUTI information having a mapping relation with the RAN UE ID alongwith the RAN UE ID. (Although not illustrated), the informationtransmitted by the RIC 1504 may be measurement information of each UEreceived from the O-DU 1501, the O-CU-CP 1503, and the O-CU-UP 1502along with the RAN UE ID. xApps of the RIC 1504 processes the receivedinformation for each UE, and transmits the processed information foreach UE to the NRT-RIC 1505 along with the RAN UE ID and/or the 5G-GUTI.

The NRT-RIC 1505 collects information for each RAN UE ID which istransmitted by the O-DU 1501, the O-CU-UP 1502, the O-CU-CP 1503, andthe RIC 1504 through an O-1 interface, make a connection to the 5G-GUTItransmitted by the RIC 1504, and stores the same. That is, the NRT-RIC1505 may also store information corresponding to each user transmittedby the O-DU 1501, the O-CU-UP 1502, the O-CU-CP 1503, and the RIC 1504on the basis of the 5G-GUTI. Further, the NRT-RIC 1505 may provide thecollected information to the OSS and/or the BSS.

The RAN UE ID may be configured on the basis of the 5G-GUTI (in whichcase the NRT-RIC 1505 may acquire the 5G-GUTI according to apredetermined or a preset rule based on the RAN UE ID) or may beconfigured such that the content of the RAN UE ID is the same as the5G-GUTI since a maximum length of the currently defined RAN UE ID is 64bits and a length of the 5G-GUTI is 62 bits. In this case, the RIC 1504may transmit only the RAN UE ID to the RIC 1504.

The RAN UE ID is only an example of a specific user identifier of theO-RAN, and the specific user identifier (or UE identifier) of the O-RANmay be used in the disclosure. The 5G-GUTI is only an example of aglobally unique identifier of the UE (or user), and the globally uniqueidentifier of the UE (or user) may be used in the disclosure.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 15 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 15 . The name of the message illustratedin FIG. 15 is only an example, and the configuration of the disclosuremay be applied to a method and a message similar to those used in thedisclosure.

FIG. 16 illustrates a procedure in which a collection server receivesinformation classified for a specific UE from a DU, a CU-UP, and a CU-CPdefined in the 3GPP according to an embodiment of the disclosure.

Referring to FIG. 16 , in operation 1600, a CU-CP 1603 generates a5G-GUTI by communicating with a UE and an AMF. The method may beperformed to be the same as the above-described method. In operation1610, a collection server 1604 transmits a SUBSCRIPTION REQUEST messageto the CU-CP 1603 and, when a specific event is generated, transmits areport classified for each specific UE. In operation 1620, the CU-CP1603 processes a request configured in operation 1610 (SUBSCRIPTIONRESPONSE message) to the collection server, in which case the RAN UE IDdefined in the 3GPP and the 5G-GUTI that is mapped to the RAN UE ID andconfigured in operation 1600 are also transmitted to the collectionserver.

The collection server may identify a UE for which the information iscollected (that is, a 5G-GUTI which the UE has) on the basis of amapping relation between the RNA UE ID and the 5G-GUTI. A detaileddescription thereof will be described below. The RAN UE ID is a uniquevalue within a 3GPP 5G NR BS and may be configured as OAM by a serviceprovider.

Although the disclosure describes an example in which the RAN UE ID andthe 5G-GUTI are transmitted through the SUBSCRIPTION RESPONSE message,the CU-CP 1603 may configure the RAN UE ID on the basis of the 5G-GUTI(in which case the 5G-GUTI may be acquired according to a predeterminedor a preset rule on the basis of the RAN UE ID received by the RIC) orthe CU-CP 1603 may configure the content of the RAN UE ID to be the sameas the 5G-GUTI since a maximum length of the currently defined RAN UE IDis 64 bits and a length of the 5G-GUTI is 62 bits. In this case, theCU-CP 1603 may transmit only the RAN UE ID to the RIC.

Further, the CU-CP 1603 may transmit the RAN UE ID (and the 5G-GUTI) tothe collection server through a message other than the SUBSCRIPTIONRESPONSE message, and the disclosure may be applied to the case.

In operation 1630, the collection server may transmit a SUBSCRIPTIONREQUEST message to the CU-UP 1602, and when a specific event isgenerated, a reports classified for each specific UE is transmitted tothe collection server. In operation 1640, the CU-UP 1602 may process arequest according to operation 1630, insert the RAN UE ID defined in the3GPP and the report for each RAN UE ID (UE-related information) into theSUBSCRIPTION RESPONSE message, and transmit the SUBSCRIPTION RESPONSEmessage.

In operation 1650, the collection server transmits a SUBSCRIPTIONREQUEST message to the DU 1601, and when a specific event is generated,a report classified for each specific UE is transmitted to thecollection server. In operation 1660, the DU 1601 processes a requestaccording to a sixth procedure, insert the RAN UE ID defined in the 3GPPand the report for each RAN UE ID (UE-related information) into theSUBSCRIPTION RESPONSE message, and transmits the SUBSCRIPTION RESPONSEmessage to the collection server.

When the preset event is generated in operation 1610, the CU-CP 1603transmits the information classified for each RAN UE ID to thecollection server through an indication message defined by thecollection server in operation 1670. The information may include one ormore RAN UE IDs and information for each RAN UE ID.

When the preset event is generated in operation 1630, the CU-UP 1602transmits the information classified for each RAN UE ID to thecollection server through an indication message defined by thecollection server in operation 1680. The information may include one ormore RAN UE IDs and information for each RAN UE ID.

When the preset event is generated in operation 1650, the DU 1601transmits the information classified for each RAN UE ID to thecollection server through an indication message defined by thecollection server in operation 1690. The information may include one ormore RAN UE IDs and information for each RAN UE ID.

The collection server identifies a 5G-GUTI associated with the RAN UE IDand store information on each RAN UE ID transmitted by the CU-CP 1603,the CU-UP 1602, and the DU 1601 in operations 1620, 1640, and 1650 to beassociated with the 5G-GUTI. That is, for one 5G-GUTI, information on aspecific user transmitted by each of the CU-CP 1603, the CU-UP 1602, andthe DU 1601 may be stored. At this time, since a plurality of CU-CPs andCU-UPs, and a plurality of DUs may be connected to the collectionserver, RAN UE IDs transmitted by the CU-CP 1603, the CU-UP 1602, andthe DU 1601 may overall each other. The collection server may identifythe 5G-GUTI on the basis of port information of the CU-CP 1603, theCU-UP 1602, and/or the DU 1601 transmitting the RAN UE ID (andinformation thereon) and the RAN UE ID or identify the 5G-GUTI on thebasis of an RAN function ID and the RAN UE ID of the CU-CP 1603, theCU-UP 1602, and/or the DU 1601.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 16 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 16 . A name of the message illustrated inFIG. 16 is only an example, and the configuration of the disclosure maybe applied to a method and message similar to those used in thedisclosure.

FIG. 17 illustrates a procedure in which a RIC receives informationclassified for a specific UE from an O-DU, an O-CU-UP, and an O-C-CPdefined in the O-RAN according to an embodiment of the disclosure.

Referring to FIG. 17 , in operation 1700, an O-CU-CP 1703 generates a5G-GUTI by communicating with a UE and an AMF. The 5G-GUTI may begenerated through the above-described method. In operation 1710, the RIC1704 transmits an E2 SUBSCRIPTION REQUEST message defined in the O-RANto the O-CU-CP 1703 and transmits a report classified for a specific UEwhen a specific event is generated. In operation 1720, the O-CU-CP 1703processes a request of the RIC 1704 according to operation 1710, andinserts a RAN UE ID defined in the 3GPP and the 5G-GUTI , which ispreset in a first procedure and mapped to the RAN UE ID, into an E2SUBSCRIPTION RESPONSE message and transmits the E2 SUBSCRIPTION RESPONSEmessage to the RIC 1704.

The RIC 1704 may identify a UE for which the information is collected(that is, a 5G-GUTI which the UE has) on the basis of a mapping relationbetween the RNA UE ID and the 5G-GUTI. A detailed description thereofwill be described below. The RAN UE ID is a unique value within a 3GPP5G NR BS, and may be configured as OAM by a service provider.

Although the disclosure describes an example in which the RAN UE ID andthe 5G GUTI are transmitted through the E2 E2-CP RIC SUBSCRIPTIONRESPONSE message, the O-CU-CP 1703 may configure the RAN UE ID on thebasis of the 5G-GUTI (in which case the 5G-GUTI may be acquiredaccording to a predetermined or a preset rule based on the RAN UE IDreceived by the RIC 1704) or the O-CU-CP 1703 may configure the contentof the RAN UE ID to be the same as the 5G-GUTI since a maximum length ofthe currently defined RAN UE ID is 64 bits and a length of the 5G-GUTIis 62 bits. In this case, the O-CU-CP 1703 may transmit only the RAN UEID to the RIC 1704.

Further, the O-CU-CP 1703 may transmit the RAN UE ID (and the 5G-GUTI)to the RIC 1704 through a message other than the E2 E2-CP RICSUBSCRIPTION RESPONSE message, and the disclosure may be applied to thecase.

In operation 1730, the RIC 1704 may transmit the E2 SUBSCRIPTION REQUESTmessage defined in the O-RAN to the O-CU-UP 1702, and when a specificevent is generated, a report classified for each specific UE istransmitted to the RIC 1704. In operation 1740, the O-CU-UP 1702processes a request of the RIC 1704 in operation 1730 and transmits theRAN UE ID defined in the 3GPP and information on each RAN UE ID to theRIC 1704 along with the SUBSCRIPTION RESPONSE message.

In operation 1750, the RIC 1704 transmits an E2 SUBSCRIPTION REQUESTmessage to the O-DU 1701, and when a specific event is generated, areport classified for each specific UE is transmitted to the RIC 1704.In operation 1760, the O-DU 1701 processes a request from the RIC 1704in operation 1750 and transmits the RAN UE ID defined in the 3GPP andinformation on each RAN UE ID to the RIC 1704 along with theSUBSCRIPTION RESPONSE message.

When the preset event is generated in operation 1710, the O-CU-CP 1703transmits information classified for each RAN UE ID to the RIC 1704through an E2 indication message defined by the RIC 1704 in operation1770. The information may include one or more RAN UE IDs and informationfor each RAN UE ID. When the preset event is generated in operation1730, the O-CU-CP 1703 transmits information classified for each RAN UEID to the RIC 1704 through an E2 indication message defined by the RIC1704 in operation 1780. The information may include one or more RAN UEIDs and information for each RAN UE ID. The information may include atleast one piece of resource state information (buffer status) in theCU-UP, bearer state information such as the number of bearers, a CPUusage state, and KPI-related information (throughput of the UE anddelay), and may be applied to the entirety of the disclosure withoutbeing limited to the example of FIG. 17 .

When the preset event is generated in operation 1750, the O-DU 1701transmits information classified for each RAN UE ID to the RIC 1704through the indication message defined by the RIC 1704 in operation1790. The information may include one or more RAN UE IDs and informationfor each RAN UE ID.

The RIC 1704 identifies a 5G-GUTI associated with the RAN UE ID andstore information for each RAN UE ID transmitted by the O-CU-CP 1703,the O-CU-UP 1702, and the O-DU 1701 in operations 1720, 1740, and 1760to be associated with the 5G-GUTI. That is, for one 5G-GUTI, informationon a specific user transmitted by each of the O-CU-CP 1703 and the O-DU1701 may be stored.

At this time, since a plurality of O-CU-CPs and O-CU-UPs and a pluralityof O-DUs may be connected to the RIC 1704, RAN UE IDs transmitted by theO-CU-CP 1703, the O-CU-UP 1702, and the O-DU 1701 may overlap eachother. At this time, the RIC 1704 may identify the 5G-GUTI on the basisof port information of the O-CU-CP 1703, the O-CU-UP 1702, and/or theO-DU 1701 transmitting the RAN UE ID (and information related thereto)and the RAN UE ID or configure the 5G-GUTI on the basis of the RANfunction ID and the RAN UE ID of the O-CU-CP 1703, the O-CU-UP 1702,and/or the O-DU.

The RAN UE ID is only an example of a specific user identifier of theO-RAN, and a specific user identifier (or UE identifier) of the O-RANmay be used in the disclosure. The 5G-GUTI is only an example of aglobally unique identifier of the UE (or user), and a globally uniqueidentifier of the UE (or user) may be used in the disclosure.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 17 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 17 . A name of the message illustrated inFIG. 17 is only an example, and the configuration of the disclosure maybe applied to a method and message similar to those used in thedisclosure. A name of the message illustrated in FIG. 17 is only anexample, and the configuration of the disclosure may be applied to amethod and message similar to those used in the disclosure.

One or more of the methods according to the disclosure may be combinedand used.

FIG. 18 illustrates an example of using a UE identifier based on a5G-GUTI is used in the O-RAN according to an embodiment of thedisclosure.

Referring to FIG. 18 , reference numeral 1800 indicates an example inwhich the O-DU measures an amount of the use of physical resource blocks(PRBs) for each network slice or each cell (interchangeably used withphysical layer resources, radio resources, or time-frequency resources),throughput, and latency and transmits information on each user to theRIC along with the RAN UE ID on the basis of the KPI report and the5G-GUTI.

Reference numeral 1810 indicates an example in which the O-CU-CPmeasures network slice-specific or cell-specific KPI and transmitsinformation on each user to the RIC along with the RAN UE ID on thebasis of the 5G-GUTI. At this time, the 5G-GUTI may also be transmitted.

Reference numeral 1820 indicates an example in which the O-CU-UPmeasures throughput for each network slice, each cell, or each bearer,and CPU usage and transmits information on each user to the RIC alongwith the RAN UE ID (and 5G-GUTI) on the basis of the 5G-GUTI such as aKPI report, resource usage, and an overload indication.

The transmitted information may be received by an E2 Termination xAppand may be stored in a database for each 5G-GUTI. The xAPP serving as aKPI monitor based on the stored information may analyze whether KPI ofeach UE is achieved, the analysis result (KPI report) may be collectedfor each UE, and generated information may be transmitted to the NRT RICthrough O1 interface xApps.

The RIC and the NRT-RIC may optimize resources to provide servicerequired for each UE on the basis of information stored for each5G-GUTI. Specifically, the RIC or the NRT-RIC may allow the UE to useadditional radio resources through carrier aggregation or dualconnectivity or control mobility of the UE.

FIG. 19 illustrates a device capable of implementing the disclosureaccording to an embodiment of the disclosure.

Referring to FIG. 19 , a device 1900 according to the disclosure mayinclude a controller 1910 and a transceiver 1920, and further include astorage unit which is not illustrated. The controller 1910 may operateto perform at least one of the functions of a RIC, an NRT-RIC, anO-CU-CP, an O-CU-UP, an O-DU, a CU-CP, a CU-UP, and a DU, and thetransceiver 1920 may be controlled by the controller 1910 to transmitand receive the messages. The storage unit may store informationincluded in a received message and information on each UE.

FIG. 20 illustrates a 3GPP non-standard alone (NSA) supporting system ofan O-RAN network system according to an embodiment of the disclosure.

Referring to FIG. 20 , the 3GPP NSA network uses dual connectivity thatsimultaneously uses 4G and 5G while supporting the conventional 4G (eNB)function and additionally using 5G (gNB). The O-RAN standard uses newlydefined non-real time RAN intelligent controller (NRT-RIC) 2000,(near-real time) RAN intelligent controller (RIC) 2010, an O-CU-CP 2020,an O-CU-UP 2030, and an O-DU 2040 and additionally supports an NSAscheme that supports an eNB 2050 of 4G LTE. At this time, the RIC 2010and/or the NRT-RIC 2000 performs near-real-time control and optimize LTEand 5G RAN elements and resources on the basis of data collected from anO-RAN O-eNB through an E2-eNB interface between the RIC 2010 and anO-eNB 2050 defined in the O-RAN. To this end, the O-eNB 2050 maytransmit call-related information and measurement-related informationfor a specific UE to the RIC 2010.

FIG. 21 illustrates a procedure in which an eNB to which a UE makes callaccess acquires a GUTI in the case of NSA EN-DC defined in the O-RANaccording to an embodiment of the disclosure. Like the 3GPP NSA, in theO-RAN NSA, a message for call access is transmitted to an MME through anO-eNB, and then dual-connectivity is supported through establishment ofan X2 interface with a gNB. Accordingly, an initial call access processis the same as 4G LTE.

Referring to FIG. 21 , in operation 2100, a UE 2101 inserts 40 bits ofan S-TMSI value allocated by the core network into an RRC connectionrequest message and transmits the RRC connection request message to anO-eNB 2102 in initial setup according to a call access procedure definedin the 3GPP standard. In operation 2110, the O-eNB 2102 stores theS-TMSI value transmitted by the UE 2101. Thereafter, the O-eNB 2102transmits an RRCConnectionSetup message to the UE 2101, and the UE 2101transmits RRCConnectionSetupComplete message to the O-eNB 2102 inresponse thereto. Thereafter, the O-eNB 2102 transmits an initial UEmessage to an MME 2103. In operation 2120, the O-eNB 2102 of the O-RANstores a GUMMEI value, which is inserted into an S1AP INITIAL CONTEXTSETUP REQUEST message and transmitted by the MME 2103, according to thecall access procedure defined in the 3GPP standard. In operation 2130,the O-RAN O-eNB 2102 identifies an M-TMSI on the basis of the S-TMSIstored in operation 2110 and generates a GUTI by concatenating theM-TMSI with a lower part of the GUMMEI received in operation 2120.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 21 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 21 .

FIG. 22 illustrates a procedure in which a CU-CP of a 5G RAN defined inthe 3GPP acquires a GUAMI when a UE performs initial attach (initialaccess) according to an embodiment of the disclosure.

Referring to FIG. 22 , when there is no 5G SAE-temporary mobilesubscriber identity (5G-S-TMSI) value allocated by the 5G core networkin initial setup, a UE 2201 performing initial attach according to thecall access procedure defined in the 3GPP standard inserts a randomvalue into an RRCSetupRequest message and transmits the RRCSetupRequestmessage in operation 2200. A DU 2202 inserts the random value receivedin operation 2200 into an F1 initial UL RRC message transfer message andtransmits the F1 initial UL RRC message transfer message to a CU-CP 2204according to the call access procedure defined in the 3GPP in operation2210. FIG. 22 also includes a CU-UP 203.

Thereafter, the CU-CP 2204 transfers a DL RRC message to the DU 2202,and the DU 2202 transmits an RRCSetup message (or an RRCReject message)to the UE 2201. The UE 2201 receiving the RRCSetup message transmits anRRCSetupComplete message to the DU 2202, and the DU 2202 transmits a ULRRC message transfer to the CU-CP 2204.

The CU-CP 2204 transmits an initial UE message to an AMF 2205, and theAMF 2205 transmits an NGAP INITIAL CONTEXT SETUP REQUEST message to theCU-CP 2204 according to the 3GPP call access procedure in operation2220. The CU-CP 2204 stores the GUAMI which is inserted into the NGAPINITIAL CONTEXT SETUP REQUEST and transmitted by the AMF 2205 inoperation 2230. In the procedure, the GUAMI stored by the CU-CP 2204 maybe used as an identifier for uniquely identifying the UE 2201 within a3GPP gNB such as a RAN UE ID, and the identifier may be replaced with a5G-GUTI in a UE additional access scenario in the future. Further, avalue based on the GUAMI rather than the GUAMI may be used as anidentifier of the UE 2201 (for example, a RAN UE ID), and such a methodis similar to a method using the 5G-GUTI as the identifier of the UE2201, and thus the described method may be referenced.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 22 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 8 .

FIG. 23 illustrates a procedure in which an eNB to which a UE makes callaccess acquires a GUMMEI in the case of 4G LTE defined in the O-RANaccording to an embodiment of the disclosure. The call access istransmitted to an MME through an O-eNB.

Referring to FIG. 23 , when there is no S-TMSI value allocated by thecore network in initial setup, a UE 2301 performing initial attachaccording to the call access procedure defined in the 3GPP standardinserts a random value into an RRC connection request message andtransmits the RRC connection request message to an O-eNB 2302 of theO-RAN in operation 2300. The O-eNB 2302 transmits an RRCConnectionSetupmessage to the UE 2301, and the UE 2301 transmitsRRCConnectionSetupComplete message to the O-eNB 2302 in responsethereto. Thereafter, the O-eNB 2302 transmits an initial UE message toan MME 2303.

The O-eNB 2302 of the O-RAN receives an S1AP INITIAL CONTEXT SETUPREQUEST message from the MME 2303 according to the call access proceduredefined in the 3GPP standard in operation 2310, and stores a GUMMEIvalue which is inserted into the S1AP INITIAL CONTEXT SETUP REQUEST andtransmitted by the MME 2303 in operation 2320. In the procedure, theGUMMEI value stored by the O-eNB 2302 may be used as an identifier foruniquely identifying the UE 2301 within a 3GPP gNB such as a RAN UE ID,and the identifier may be replaced with a GUTI in a UE additional accessscenario in the future. Further, a value based on the GUMMEI rather thanthe GUMMEI may be used as an identifier of the UE 2301 (for example, aRAN UE ID), and such a method is similar to a method using the 5G-GUTIor the GUTI as the identifier of the UE 2301, and thus the describedmethod may be referenced.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 23 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 23 .

FIG. 24 illustrates an example of a procedure in which an O-CU-CP of a5G RAN defined in the O-RAN allocates a unique RAN UE ID to a serviceprovider network allocated by the core network when a UE performsinitial attach according to an embodiment of the disclosure.

Referring to FIG. 24 , a UE 2401 performs an RRC setup procedure with anO-DU 2402 and an O-CU-CP 2404 according to the call access proceduredefined in the 3GPP standard, and the procedure may refer to FIG. 8 . Inoperation 2400, the O-CU-CP 2404 transmits an NGAP initial UE messageincluding a RAN UE ID defined in initial setup or configured by the OAMto the AMF. Alternatively, the O-CU-CP 2404 may transmit the RAN UE IDwithout inserting the RAN UE ID into the NGAP initial UE message. Inoperation 2410, the AMF 2405 stores the RAN UE ID, which is insertedinto the NGAP initial UE message and transmitted by the O-CU-CP 2404according to the call access procedure defined in the 3GPP standard, asa 5G-GUTI that is a value for globally uniquely identifying the UE 2401newly configured by the AMF 2405. That is, the RAN UE ID is configuredas the 5G-GUTI.

Further, rather than the 5G-BUTI, a combination of a value based on the5G-GUTI or a GUAMI and a new user identifier, a value based on a GUAMIand a new user identifier, a value shared with the core networkincluding a GUAMI, or a value based on a value shared with the corenetwork including a GUAMI may be used as a RAN UE ID or an identifier ofthe UE 2401 (in the O-RAN) (for example, a GUAMI and a new useridentifier). The value shared with the core network may be the valuedescribed with reference to FIG. 14 . A method of using informationother than the 5G-GUTI as the RAN UE ID or the identifier of the UE 2401may refer to a method of identifying the UE 2401 within a serviceprovider PLMN. That is, the RAN UE ID or the identifier of the UE 2401may be determined on the basis of the identifier of the UE 2401 usedwithin the service provider PLMN.

In operation 2420, the AMF 2405 inserts the RAN UE ID stored inoperation 2410 into an NGAP INITIAL CONTEXT SETUP REQUEST message andtransmits the NGAP INITIAL CONTEXT SETUP REQUEST message to the O-CU-CP2404 according to the call access procedure defined in the 3GPPstandard. The O-CU-CP 2404 stores the RAN UE ID which is inserted intothe NGAP INITIAL CONTEXT SETUP REQUEST message and transmitted by theAMF 2405 according to the call access procedure defined in the 3GPPstandard.

Thereafter, the UE 2401 and the O-CU-CP 2404 may perform an RRCreconfiguration procedure according to the 3GPP standard, and theO-CU-CP 2404 may insert the stored RAN UE ID into an NGAP INITIALCONTEXT SETUP RESPONSE message and transmits the NGAP INITIAL CONTEXTSETUP RESPONSE message to the AMF 2405 in response to the NGAP INITIALCONTEXT SETUP REQUEST.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 9 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 24 . FIG. 24 also includes an O-CU-UP2403.

FIG. 25 illustrates an example of a procedure in which an O-RAN eNB(O-eNB) (or eNB) in the 5G NSA and O-RAN LTE network structure definedin the O-RAN allocates a unique RAN UE ID to a service provider networkallocated by the core network when a UE performs initial attachaccording to an embodiment of the disclosure.

Referring to FIG. 25 , a UE 2501 performs an RRC connection setupprocedure with an O-eNB 2502 according to the call access proceduredefined in the 3GPP standard, and the procedure may refer to FIG. 10 .In operation 2500, the O-eNB 2502 inserts a RAN UE ID defined in initialsetup or configured by the OAM into an 51 initial UE message andtransmits the 51 initial UE message to the MME 2503. Alternatively, theO-eNB 2502 may transmit the RAN UE ID without inserting the RAN UE IDinto the S1 initial UE message. In operation 2510, the MME stores theRAN UE ID, which is inserted into the S1 initial UE message andtransmitted by the O-eNB 2502 according to the call access proceduredefined in the 3GPP standard, as a GUTI that is a value for globallyuniquely identifying the UE 2501 newly configured by the MME. That is,the RAN UE ID is configured as the GUTI.

Further, rather than the GUTI, a combination of a value based on theGUTI or a GUMMEI and a new user identifier, a value based on a GUMMEIand a new user identifier, a value shared with the core networkincluding a GUMMEI, or a value based on a value shared with the corenetwork including a GUMMEI may be used as a RAN UE ID or an identifierof the UE 2501 (in the O-RAN) (for example, a GUMMEI and a new useridentifier). The value shared with the core network may be the valuedescribed with reference to FIG. 14 . A method of using informationother than the GUTI as the RAN UE ID or the identifier of the UE 2501may refer to a method of identifying the UE 2501 within a serviceprovider PLMN. That is, the RAN UE ID or the identifier of the UE 2501may be determined on the basis of the identifier of the UE 2501 usedwithin the service provider PLMN.

In operation 2520, the MME inserts the RAN UE ID stored in operation2510 into an S1 INITIAL CONTEXT SETUP REQUEST message and transmits theS1 INITIAL CONTEXT SETUP REQUEST message according to the call accessprocedure defined in the 3GPP standard. The O-eNB 2502 stores the RAN UEID which is inserted into the S1 INITIAL CONTEXT SETUP REQUEST messageand transmitted by the MME according to the call access proceduredefined in the 3GPP standard. Thereafter, the O-eNB 2502 may transmit anS1 INITIAL CONTEXT SETUP RESPONSE message including the stored RAN UE IDto the MME in response to the S1 INITIAL CONTEXT SETUP REQUEST message.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 25 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 25 .

FIG. 26 illustrates an example of a procedure in which an O-CU-CP of a5G RAN defined in the O-RAN allocates a RAN UE NGAP ID used for NGAPconfiguration with the core network as a RAN UE ID when a UE 2501performs initial attach according to an embodiment of the disclosure.

Referring to FIG. 26 , a UE 2601 performs an RRC setup procedure with anO-DU 2602 and an O-CU-CP 2604 according to the call access proceduredefined in the 3GPP standard, and the procedure may refer to FIG. 8 .Specifically, the UE 2601 transmits an RRCSetupRequest message to theO-DU 2602 in operation 2600, and the O-DU 2602 transmits an F1 initialUL RRC message transfer message to the O-CU-CP 2604 according to thecall access procedure defined in the 3GPP standard in operation 2610.Thereafter, the O-CU-CP 2604 transfers a DL RRC message to the O-DU2602, and the O-DU 2602 transmits an RRCSetup message to the UE 2601.The UE 2601 receiving the RRCSetup message transmits an RRCSetupCompletemessage to the O-DU 2602 in operation 2620, and the O-DU 2602 transmitsa UL RRC Message Transfer to the O-CU-CP 2604 in operation 2630.

The O-CU-CP 2604 configures a RAN UE NGAP ID defined in initial setup orused by an NGAP interface with the AMF 2605 as a RAN UE ID and transmitsan NGAP Initial UE message to the AMF 2605 in operation 2640.Alternatively, the O-CU-CP 2604 may transmit the RAN UE ID withoutinserting the RAN UE ID into the NGAP Initial UE message. A detaileddescription of the RAN UE NGAP ID is made with reference to FIG. 27 .The RAN UE NGAP ID may be integers of 32 bits, but is not limitedthereto.

The AMF 2605 stores the RAN UE ID configured as the RAN UE NGAP ID,which is inserted into the NGAP initial UE message and transmitted bythe O-CU-CP 2604 according to the call access procedure defined in the3GPP standard, or stores the RAN UE ID as a 5G-GUTI that is a value forglobally uniquely identifying the UE 2601 newly configured by the AMF.That is, the RAN UE ID is configured as a RAN UE NGAP ID or a 5G-GUTI(by the AMF).

Further, a combination of a value based on the 5G-GUTI or a GUAMI and anew user identifier, a value based on a GUAMI and a new user identifier,a value shared with the core network including a GUAMI, or a value basedon a value shared with the core network including a GUAMI may be used asa RAN UE ID or an identifier of the UE 2601 (in the O-RAN) (for example,a GUAMI and a new user identifier) rather than using the 5G-GUTI as theRAN UE ID. The value shared with the core network may be the valuedescribed with reference to FIG. 14 . Alternatively, a method of usinginformation other than the 5G-GUTI as the RAN UE ID or the identifier ofthe UE 2601 may refer to a method of identifying the UE 2601 within aservice provider PLMN. That is, the RAN UE ID or the identifier of theUE 2601 may be determined on the basis of the identifier of the UE 2601used within the service provider PLMN.

In operation 2650, the AMF 2605 inserts the stored RAN UE ID into anNGAP INITIAL CONTEXT SETUP REQUEST message and transmits the NGAPINITIAL CONTEXT SETUP REQUEST message to the O-CU-CP 2604 according tothe call access procedure defined in the 3GPP standard. The O-CU-CP 2604stores the RAN UE ID which is inserted into the NGAP INITIAL CONTEXTSETUP REQUEST message and transmitted by the AMF according to the callaccess procedure defined in the 3GPP standard.

Thereafter, the UE 2601 and the O-CU-CP 2604 may perform an RRCreconfiguration procedure according to the 3GPP standard, and theO-CU-CP may insert the stored RAN UE ID into an NGAP INITIAL CONTEXTSETUP RESPONSE message and transmits the NGAP INITIAL CONTEXT SETUPRESPONSE message to the AMF in response to the NGAP INITIAL CONTEXTSETUP REQUEST. Thereafter, the O-CU-CP 2604 may insert the RAN UE IDinto an E2 indication message and transmits the E2 indication message toa RIC 2606, and at least one node of the O-DU 2602 and the O-CU-UP 2603may also transmit the E2 indication message to the RIC 2606.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 26 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 26 .

FIG. 27 illustrates a RAN UE NGAP ID specified in the 3GPP standardaccording to an embodiment of the disclosure.

Referring to FIG. 27 , the RAN UE NGAP ID is an identifier used in theRAN when the O-CU-CP 2604 and the AMF establish the NGAP connection.This is an identifier of uniquely identifying the UE (or associationwith the UE) in an NG interface with a BS (gNB or an NG-RAN node).

FIG. 28 illustrates an example of a procedure in which an O-CU-CP of a5G RAN defined in the O-RAN allocates an AMF UE NGAP ID used for NGAPconfiguration with the core network as a RAN UE ID when a UE performsinitial attach according to an embodiment of the disclosure.

Referring to FIG. 28 , a UE 2801 performs an RRC setup procedure with anO-DU 2802 and an O-CU-CP 2804 according to the call access proceduredefined in the 3GPP standard, and the procedure may refer to FIG. 8 .Specifically, the UE 2801 transmits an RRCSetupRequest message to theO-DU 2802 in operation 2800, and the O-DU 2802 transmits an F1 initialUL RRC message transfer message to the O-CU-CP 2804 according to thecall access procedure defined in the 3GPP standard in operation 2810.Thereafter, the O-CU-CP 2804 transfers a DL RRC message to the O-DU2802, and the O-DU 2802 transmits an RRCSetup message to the UE 2801.The UE 2801 receiving the RRCSetup message transmits an RRCSetupCompletemessage to the O-DU 2802 in operation 2820, and the O-DU 2802 transmitsa UL RRC Message Transfer to the O-CU-CP 2804 in operation 2830.

The O-CU-CP 2804 configures a RAN UE NGAP ID defined in initial setup orused by an NGAP interface with the AMF 2806 as a RAN UE ID and transmitsan NGAP Initial UE message to the AMF 2806 in operation 2840.Alternatively, the O-CU-CP 2804 may transmit the RAN UE ID withoutinserting the RAN UE ID into the NGAP Initial UE message. A detaileddescription of the RAN UE NGAP ID is made with reference to FIG. 27 .The RAN UE NGAP ID may be integers of 64 bits, but is not limitedthereto.

The AMF 2806 configures the RAN UE ID (configured as the RAN UE NGAP ID,which is inserted into the NGAP initial UE message and transmitted bythe O-CU-CP) according to the call access procedure defined in the 3GPPstandard as the 5G-GUTI that is a value for globally uniquelyidentifying the UE 2801 newly configured by the AMF 2806 or allocatesand stores an AMF UE NGAP ID used for identifying the UE 2801 by theAMF. That is, the RAN UE ID is configured as an AMF UE NGAP ID or a5G-GUTI (by the AMF). Further, a combination of a value based on a5G-GUTI, a combination of a GUAMI and a new user identifier, a valuebased on a GUAMI and a new user identifier, a value shared with the corenetwork including a GUAMI, or a value based on a value shared with thecore network including a GUAMI may be used as a RAN UE ID or anidentifier of the UE 2801 (in the O-RAN) rather than using the 5G-GUTIas the RAN UE ID.

FIG. 29 illustrates the detailed configuration of an AMF UE NGAP IDaccording to an embodiment of the disclosure.

Referring to FIG. 29 , the AMF UE NGAP ID is an identifier allocated touniquely identify a UE in an NG interface with an AMF, and may beuniquely configured within an AMF set. For example, the AMF UE NGAP IDmay be 40 bits, and when the BS receives the AMF UE NGAP ID, the BSshould store the AMF UE NGAP ID of a specific UE while a UE-relatedlogical NG-connection of the specific UE is maintained, and the AMF UENGAP ID should be inserted into NGAP signaling. In the case of LTE, anMME UE S1AP ID may be used instead of the AMF UE NGAP ID.

FIG. 30 illustrates the configuration of an MME UE S1AP ID according toan embodiment of the disclosure.

Referring to FIG. 30 , similar to the AMF UE NGAP ID, the MME UE S1AP IDis an identifier allocated to uniquely identify a UE connected to oneMME through an S1-MME interface and may be 32 bits. In the case of anLTE system, the MME instead of the AMF of FIG. 28 may allocate the MMEUE S1AP ID as the RAN UE ID. Further, any identifier used foridentifying the UE by the AMF or the MME may replace the AMF UE NGAP IDor the MME UE S1AP ID without using the AMF UE NGAP ID and the MME UES1AP ID.

Alternatively, the AMF (or MME) may generate a bitstream by applying128-bit or 256-bit SECURE HASH FUNCTION defined in the 3GPP or SECUREHASH FUNCTION defined in national institute of standards and technology(NIST) or Internet engineering task force (IETF) to the generated RAN UEID, truncate the bitstream by 64 bits according to the 64 bitscorresponding to the length of the RAN UE ID, and then configure thesame as the RAN UE ID. This may be the application of a securityfunction to make finding the conventional AMF NGAP UE ID (or MME UE S1APID) or the 5G-GUTI impossible on the basis of the RAN UE ID. Thedetailed content of SECURE HASH(SH) 64bits TRUNCATION is illustrated inFIG. 31 .

FIG. 31 illustrates an example of generating 128 bits through AES-CMACon the basis of the AMF UE NGAP ID or the MME UE S1AP ID, truncatingupper 64 bits of the generated 128 bits, and generating lower 64 bits asan SH-AMF UE NGAP ID or an SH-MME UE S1AP ID to use the same as the RANUE ID according to an embodiment of the disclosure.

Referring to FIG. 31 , the UE identifier of 64 bits may be an ID foruniquely identifying the UE in an AMF pool or an MME pool. FIG. 31 isonly an example of generating the identifier of the UE through the hashfunction, and the disclosure is not limited thereto.

The value shared with the core network may be the value described withreference to FIG. 14 . Alternatively, a method of using informationother than the 5G-GUTI as the RAN UE ID or the identifier of the UE mayrefer to a method of identifying the UE within a service provider PLMN.That is, the RAN UE ID or the identifier of the UE may be determined onthe basis of the identifier of the UE used within the service providerPLMN.

In operation 2850, the AMF 2806 inserts the stored RAN UE ID into anNGAP INITIAL CONTEXT SETUP REQUEST message and transmits the NGAPINITIAL CONTEXT SETUP REQUEST message to the O-CU-CP 2804 according tothe call access procedure defined in the 3GPP standard. The O-CU-CP 2804stores, as the RAN UE ID, the AMF UE NGAP ID which is inserted into theNGAP INITIAL CONTEXT SETUP REQUEST message and transmitted by the AMF2806 according to the call access procedure defined in the 3GPPstandard.

Alternatively, the O-CU-CP 2804 may generate a bitstream by applying theSECURE HASH FUNCTION defined in the 3GPP or the 128-bit or 256-bitSECURE HASH FUNCTION defined in the NIST or IETF to the AMF UE NGAP ID,which is inserted in to the NGAP INITIAL CONTEXT SETUP REQUEST messageand transmitted by the AMF 2906, truncate the bitstream by 64 bitsaccording to 64 bits corresponding to the length of the RAN UE ID, andconfigure the same as the RAN UE ID. This may be the application of asecurity function to make finding the conventional AMF NGAP UE ID or the5G-GUTI impossible on the basis of the RAN UE ID.

The O-CU-CP 2804 inserts the configured RAN UE ID into an E1 BearerContext Setup Request message specified in the 3GPP standard, transmitsthe E1 Bearer Context Setup Request message to the O-CU-UP 2803, andreceives an E1 Bearer Context Setup Response message in operations 2860and 2870, and also inserts the RAN UE ID into an F1 UE CONTEXT SETUPREQUEST message specified in the 3GPP standard, transmits the F1 UECONTEXT SETUP REQUEST message to the O-DU 2802, and receives an F1 UECONTEXT SETUP RESPONSE message in operations 2880 and 2890.

Thereafter, the UE 2801 and the O-CU-CP 2804 performs an RRCreconfiguration procedure according to the 3GPP standard, and theO-CU-CP 2804 inserts the stored RAN UE ID into an NGAP INITIAL CONTEXTSETUP RESPONSE message and transmits the NGAP INITIAL CONTEXT SETUPRESPONSE message to the AMF 2806 in response to the NGAP INITIAL CONTEXTSETUP REQUEST.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 28 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 28 .

FIG. 32 illustrates a procedure in which an O-CU-CP of a 5G RAN definedin the O-RAN generates a list of information for each UE on the basis ofa 5G-S-TMSI, GUAMI, and AMF UE NGAP ID for each RAT/frequency selectionpriority (RFSP) group received from a UE and an AMF and transmits thelist to a RIC, and the RIC generates a list of the information for eachUE on the basis of at least one of the 5G-S-TMSI, GUAMI, and AMF UE NGAPID for each RFSP group, allocates a UE ID, and transmits the informationto an NRT-RIC through an A1 enrichment information message, and the NRTRIC performs management related to a UE ID for each RFSP group accordingto an embodiment of the disclosure.

Referring to FIG. 32 , in operation 3200, a UE 3201 inserts upper 39bits of a 5G-S-TMSI value (or random value and, hereinafter, may beinterchangeably used with a random value) allocated by the core networkinto an RRCSetupRequst message in initial setup according to the callaccess procedure defined in the 3GPP standard and transmits theRRCSetupRequest message to an O-DU 3202. In operation 3210, the O-DU3202 inserts the upper 39 bits of the 5G-S-TMSI value received inoperation 3200 into an F1 initial UL RRC message transfer message andtransmits the F1 initial UL RRC message transfer message to an O-CU-CP3204 according to the call access procedure defined in the 3GPPstandard. In operation 3215, the O-CU-CP 3204 stores the upper 39 bitsof the 5G-S-TMSI value, which was inserted into the F1 message andtransmitted by the O-DU 3202. Thereafter, the O-CU-CP 3204 transfers aDL RRC message to the O-DU 3202 in operation 3220, and the O-DU 3202transmits an RRCSetup message (or an RRCReject message) to the UE inoperation 3225.

When the O-DU 3202 transmits the RRCSetup message, the UE inserts lower9 bits of the 5G-S-TMSI value allocated by the core network into anRRCSetupComplete message in the initial setup and transmits theRRCSetupComplete message to the O-DU 3202 according to the call accessprocedure defined in the 3GPP standard in operation 3230. In operation3235, the O-DU 3202 inserts the lower 9 bits of the 5G-S-TMSI valuereceived in operation 3230 into an F1 UL RRC message transfer messageand transmits the F1 UL RRC message transfer message to the O-CU-CP 3204according to the call access procedure defined in the 3GPP standard. Inoperation 3240, the O-CU-CP 3204 stores the lower 9 bits of the5G-S-TMSI value, which was inserted into the F1 message and transmittedby the O-DU 3202. The O-CU-CP 3204 transmits an initial UE message to anAMF 3205 in operation 3245, and stores at least one of a GUAMI value, anAMF UE NGAP ID, and an RFSP value, which is inserted into a NGAP INITIALCONTEXT SETUP REQUEST message and transmitted by the AMF, according tothe call access procedure defined in the 3GPP standard in operation3250. The RFSP is a RAT/frequency selection priority and is used todesignate a specific service group to which the UE 3201 belongs in a 5Gsystem.

An NRT RIC 3207 transmits a policy related to the specific RFSP group toa RIC 3206 through an A1 policy message regardless of the order of theprocedure in operation 3255.

Thereafter, the O-CU-CP 3204 performs RIC subscription proceduresspecified in the O-RAN standard with the RIC 3206, inserts at least oneof a GUAMI, 5G-S-TMSI, and AMF UE NGAP ID of each UE having the RFSP asa representative key into an E2 indication (report) message on the basisof at least one of GUAMI, 5G-S-TMSI, and AMF UE NFAP ID of UEs belongingto the specific group RFSP designated through a subscription message bythe RIC 3206 and transmits the E2 indication (report) message to the RIC3206 in operation 3260. The RIC 3206 assigns a UE ID to each UE on thebasis of the GUAMI, 5G-S-TMSI, AMF UE NGAP ID of UEs belongings to theRFSP received through the E2 indication message and stores at least oneof the RFSP GUAMI, 5G-S-TMSI, and AMF UE NGAP ID for each UE ID inoperation 3265.

The RIC 3206 transmits a UE ID list to the NRT RIC 3207 in response tothe A1 policy message or the A1 enrichment info message as the part ofthe A1 enrichment procedure in operation 3270. The UE ID list includedin the response message includes at least one of the RFSP GUAMI,5G-S-TMSI, and AMF UE NGAP ID of each UE.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 32 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 32 . FIG. 32 also includes an O-CU-UP3203.

FIG. 33 illustrates a procedure in which an O-eNB of a 4G RAN defined inthe O-RAN generates a list of information for each UE on the basis of atleast one of an S-TMSI, GUMMEI, and MME UE S1AP ID for each subscriberprofile ID (SPID) group received from a UE and an MME and transmits thelit to a RIC, and the RIC allocates a UE ID for each UE on the basis ofat least one of the S-TMSI, GUMMEI, and MME UE S1AP ID for each SPIDgroup, generates and manages a UE list (which may include theinformation), and transmits the information to an NRT RIC 3207 throughan A1 enrichment information message, and the NRT RIC 3207 performsmanagement related to a UE ID for each SPID group according to anembodiment of the disclosure.

Referring to FIG. 33 , in operation 3300, a UE 3301 inserts upper 40bits of an S-TMSI value (or a random value and, hereinafter, may beinterchangeably used with a random value) allocated by the core networkinto an RRC Connection Request message in initial setup according to thecall access procedure defined in the 3GPP standard and transmits the RRCConnection Request message to an O-eNB 3302. In operation 3310, theO-eNB 3302 stores the S-TMSI value transmitted by the UE 3301.Thereafter, the O-eNB 3302 transmits an RRCConnectionSetup message tothe UE 3301, and the UE 3301 transmits RRCConnectionSetupCompletemessage to the O-eNB 3302 in response thereto. Thereafter, the O-eNB3302 transmits an initial UE message to an MME 3303. In operation 3320,the O-eNB 3302 stores at least one of an SPID, GUMMEI, and MME UE S1APID which is inserted into an S1AP INITIAL CONTEXT SETUP REQUEST messageand transmitted by the MME 3303, according to the call access proceduredefined in the 3GPP standard. The SPID is a subscription profile ID andis used to designate a specific service group to which the UE 3301belongs in an LTE system.

An NRT RIC 3305 transmits a policy related to the specific SPID group toa RIC 3304 through an A1 policy message regardless of the order of theprocedure in operation 3330.

Thereafter, the O-eNB 3302 performs RIC subscription proceduresspecified in the O-RAN standard with the RIC 3304, inserts at least oneof the GUAMI, S-TMSI, and MME UE S1AP ID of each UE having the SPID as arepresentative key into an E2 indication (report) message on the basisof at least one of a GUMMEI, S-TMSI, and MME UE S1AP ID of UEs belongingto the specific group SPID designated through a subscription message bythe RIC 3304 and transmits the E2 indication (report) message to the RIC3304 in operation 3340. The RIC 3304 assigns a UE ID for each UE to theinformation on the basis of at least one of the GUMMEI, S-TMSI, and MMEUE S1AP ID of UEs belonging to the SPID transmitted through the E2indication message and stores at least one of the SPID GUMMEI, S-TMSI,and MME UE S1AP ID for each UE ID in operation 3350. The RIC 3304transmits a UE ID list to the NRT RIC 3305 in response to the A1 policymessage or the A1 enrichment info message as the part of the A1enrichment procedure in operation 3360. The UE ID list included in theresponse message includes at least one of the UE ID, SPID GUAMI, S-TMSI,and MME UE S1AP ID of each UE.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 33 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 33 .

FIG. 34 illustrates a procedure in which an O-CU-CP of a 5G RAN definedin the O-RAN generates a list for each UE on the basis of a 5G-S-TMSI,GUAMI, and AMF UE NGAP ID for each RFSP group received from a UE and anAMF and transmits the list to a RIC, and the RIC generates a list of theinformation for each UE on the basis of a 5G-S-TMSI, GUAMI, and AMF UENGAP ID for each RFSP group, generates a secure hashed 5G-GUTI aftergenerating a 5G-GUTI on the basis of the 5G-S-TMSI and the GUAMI orgenerates a secure hashed 5G-GUTI using the GUAMI as a key, andtransmits the UE ID and at least one of the secure hashed 5G-GUTI, RFSP,and GUAMI to the NRT-RIC through an A1 enrichment information message,and the NRT RIC performs management related to a UE ID for each RFSPgroup according to an embodiment of the disclosure.

Referring to FIG. 34 , in operation 3400, a UE 3401 inserts upper 39bits of a 5G-S-TMSI value (or random value and, hereinafter, may beinterchangeably used with a random value) allocated by the core networkinto an RRCSetupRequst message in initial setup according to the callaccess procedure defined in the 3GPP standard and transmits theRRCSetupRequest message to an O-DU 3402. In operation 3410, the O-DU3402 inserts the upper 39 bits of the 5G-S-TMSI value received inoperation 3400 into an F1 initial UL RRC message transfer message andtransmits the F1 initial UL RRC message transfer message to an O-CU-CP3404 according to the call access procedure defined in the 3GPPstandard. In operation 3415, the O-CU-CP 3404 stores the upper 39 bitsof the 5G-S-TMSI value, which was inserted into the F1 message andtransmitted by the O-DU 3402. Thereafter, the O-CU-CP 3404 transfers aDL RRC message to the O-DU 3402 in operation 3420, and the O-DU 3402transmits an RRCSetup message (or an RRCReject message) to the UE 3401in operation 3425.

When the O-DU 3402 transmits the RRCSetup message, the UE 3401 insertslower 9 bits of the 5G-S-TMSI value allocated by the core network intoan RRCSetupComplete message in the initial setup and transmits theRRCSetupComplete message to the O-DU 3402 according to the call accessprocedure defined in the 3GPP standard in operation 3430. In operation3435, the O-DU 3402 inserts the lower 9 bits of the 5G-S-TMSI valuereceived in operation 3430 into an F1 UL RRC message transfer messageand transmits the F1 UL RRC message transfer message to the O-CU-CP 3404according to the call access procedure defined in the 3GPP standard. Inoperation 3440, the O-CU-CP 3404 stores the lower 9 bits of the5G-S-TMSI value, which was inserted into the F1 message and transmittedby the O-DU 3402. The O-CU-CP 3404 transmits an initial UE message to anAMF 3405 in operation 3445, and stores at least one of a GUAMI value, anAMF UE NGAP ID, and an RFSP value, which is inserted into a NGAP INITIALCONTEXT SETUP REQUEST message and transmitted by the AMF, according tothe call access procedure defined in the 3GPP standard in operation3450. The RFSP is a RAT/frequency selection priority and is used todesignate a specific service group to which the UE 3401 belongs in a 5Gsystem.

An NRT RIC 3407 transmits a policy related to the specific RFSP group toa RIC 3406 through an A1 policy message regardless of the order of theprocedure in operation 3455.

Thereafter, the O-CU-CP 3404 performs RIC subscription proceduresspecified in the O-RAN standard with the RIC 3406, inserts at least oneof a GUAMI, 5G-S-TMSI, and AMF UE NGAP ID of each UE having arepresentative factor as the RFSP into an E2 indication (report) messageon the basis of at least one of GUAMI, 5G-S-TMSI, and AMF UE NFAP ID ofUEs belonging to the specific group RFSP designated through asubscription message by the RIC 3406 and transmit the E2 indication(report) message to the RIC 3406 in operation 3460. The RIC 3406 assignsa UE ID to each UE on the basis of at least one of the GUAMI, 5G-S-TMSI,AMF UE NGAP ID of UEs belongings to the RFSP received through the E2indication message and stores at least one of the RFSP GUAMI, 5G-S-TMSI,and AMF UE NGAP ID for each UE ID in a RIC UE ID registry. Thereafter,the RIC 3406 generates a 5G-GUTI by concatenating the 5G-S-TMSI storedfor each UE ID newly assigned and the GUAMI stored therewith inoperation 3465. The generated 5G-GUTI is input into a secure hashfunction and a secure hashed 5G-GUTI is generated. According tocircumstances, the 5G-GUTI and the GUAMI are input into a secure hashfunction and a secure hashed 5G-GUTI is generated. At this time, theGUAMI may be selectively used as a key of the 5G-GUTI. The procedure maybe selectively applied in operation 3465.

The RIC 3406 transmits at least one of the UE ID, RFSP, GUAMI, and5G-GUTI or secure hashed 5G-GUTI to the NRT RIC 3407 in response to theA1 policy message or the A1 enrichment info message as the part of theA1 enrichment procedure in operation 3470. Further, the response messageof the A1 enrichment info message may include at least one of the UE ID,RFSP GUAMI, 5G-S-TMSI, and AMF UE NGAP ID for each UE ID.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 34 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 34 . FIG. 34 also includes an O-CU-UP3403.

FIG. 35 illustrates a procedure in which an O-eNB of a 4G RAN defined inthe O-RAN generates a list of information for each UE on the basis of atleast one of an S-TMSI, GUMMEI, and MME UE S1AP ID for each SPID groupreceived from a UE and an MME, transmits the list to a RIC, the RICgenerates, for the NRT RIC, a list for each UE on the basis of at leastone of the S-TMSI, GUMMEI, and MME UE S1AP ID for each SPID group,generates a secure hashed GUTI after generating a GUTI using the S-TMSIand the GUMMEI or generates a secure hashed GUTI using the GUMMEI as akey, and transmits the UE ID and at least one of the secure hashed GUTI,SPID, and GUMMEI to the NRT-RIC through an Al enrichment informationmessage, and the NRT RIC performs management related to a UE ID for eachSPID group according to an embodiment of the disclosure.

Referring to FIG. 35 , in operation 3500, a UE 3501 inserts upper 40bits of an S-TMSI value (or a random value and, hereinafter, may beinterchangeably used with a random value) allocated by the core networkinto an RRC Connection Request message in initial setup according to thecall access procedure defined in the 3GPP standard and transmits the RRCConnection Request message to an O-eNB 3502. In operation 3510, theO-eNB 3502 stores the S-TMSI value transmitted by the UE 3501.Thereafter, the O-eNB 3502 transmits an RRCConnectionSetup message tothe UE 3501, and the UE 3501 transmits RRCConnectionSetupCompletemessage to the O-eNB 3502 in response thereto. Thereafter, the O-eNB3502 transmits an initial UE message to an MME 3503. In operation 3520,the O-eNB 3502 stores at least one of an SPID, GUMMEI, and MME UE S1APID which is inserted into an S1AP INITIAL CONTEXT SETUP REQUEST messageand transmitted by the MME 3503, according to the call access proceduredefined in the 3GPP standard. The SPID is a subscription profile ID andis used to designate a specific service group to which the UE 3501belongs in an LTE system.

An NRT RIC 3505 transmits a policy related to the specific SPID group tothe RIC 3504 through an A1 policy message regardless of the order of theprocedure in operation 3530.

Thereafter, the O-eNB 3502 performs RIC subscription proceduresspecified in the O-RAN standard with the RIC 3504, inserts at least oneof the GUMMEI, S-TMSI, and MME UE S1AP ID of each UE having the SPID asa representative key into an E2 indication (report) message on the basisof at least one of the GUMMEI, S-TMSI, and MME UE S1AP ID of UEsbelonging to the specific group SPID designated through a subscriptionmessage by the RIC 3504 and transmits the E2 indication (report) messageto the RIC 3504 in operation 3540. The RIC 3504 assigns a UE ID for eachUE to the information on the basis of at least one of the GUMMEI,S-TMSI, and MME UE S1AP ID of UEs belonging to the SPID received throughthe E2 indication message and stores at least one of the SPID GUMMEI,S-TMSI, and MME UE S1AP ID for each UE ID in a RIC UE ID registry.Thereafter, the RIC 3504 generates a GUTI by concatenating the S-TMSIstored for each UE ID newly assigned and the GUMMEI stored therewith inoperation 3550. The generated GUTI is input into a secure hash functionand a secure hashed GUTI is generated. The GUMMEI may be selectivelyused as a key of the GUTI according to a secure hash algorithm Theprocedure may be selectively applied in operation 3550.

The RIC 3504 transmits at least one of the UE ID, SPID, GUMMEI, and GUTIor secure hashed GUTI for each UE ID to the NRT RIC 3505 in response tothe A1 policy message or the A1 enrichment info message as the part ofthe A1 enrichment procedure in operation 3560. The UE ID list includedin the response message of the A1 Enrichment Info message includes atleast one of the UE ID, SPID GUMMEI, S-TMSI, and MME UE S1AP ID of eachUE.

In the procedure, operations must not be sequentially performed or alloperations must not be necessarily performed, and the order thereof maybe changed or a specific operation may be omitted. Further, anotherconfiguration illustrated in FIG. 35 may be added to the procedure, or aprocedure illustrated in another figure may be combined with theprocedure illustrated in FIG. 35 .

FIG. 36 illustrates a RIC UE ID registry stored by a RIC according to anembodiment of the disclosure.

Referring to FIG. 36 , the RIC UE ID registry stores a RFSP, a5G-S-TMSI, a GUAMI, and an AMF UE NGAP ID for each UE ID allocated by aRIC in the case of 5G system, and stores an SPID, an S-TMSI, a GUMMEI,and an MME UE S1AP ID in the case of a 4G system.

FIG. 37 illustrates an NRT-RIC UE ID registry stored by an NRT-RICaccording to an embodiment of the disclosure.

Referring to FIG. 37 , the NRT-RIC UE ID registry stores each UE IDreceived by a RIC for each group ID (a RFSP in the case of a 5G systemand an SPID in the case of a 4G system) managed by the NRT-RIC, and asecure hashed 5G-GUTI (in the case of a 5G system) or a secure hashedGUTI (in the case of a 4G system).

FIG. 38 illustrates a method by which a RIC generates a secure hashed5G-GUTI/secure hashed GUTI according to an embodiment of the disclosure.

Referring to FIG. 38 , in the case of a 5G system, the RIC may generatea 5G-GUTI by concatenating a 5G-S-TMSI (or a random value) received froman O-CU-CP and a GUAMI and generates a secure 5G-GUTI by inputting the5G-GUTI into a secure hash function. In the case of a 4G system, the RICmay generate a GUTI by concatenating an S-TMSI received from an O-eNBand a GUMMEI and generate a secure GUTI by inputting the GUTI into asecure hash function. The 5G-GUTI and the GUTI may be replaced withother UE identifiers used in the network.

While the disclosure has been shown and described with reference tovarious embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the disclosure as definedby the appended claims and their equivalents.

What is claimed is:
 1. A method performed an O-RAN central unit-controlplane (O-CU-CP) in a communication system, the method comprising:receiving, from a network node for managing a mobility, an initialcontext setup message including an identifier of a user equipment (UE);identifying the identifier of the UE; identifying a UE ID (UE identity)of the UE; and transmitting, to a near-real time RAN intelligentcontroller (RIC), an indication message for a report, the indicationmessage including the UE ID and information associated with the UE perthe UE ID, wherein the UE ID comprises a radio access network (RAN) UEID for identifying the UE uniquely for El interface.
 2. The method ofclaim 1, wherein the identifier of the UE comprises a globally uniqueaccess and mobility management function identifier (GUAMI) or an accessand mobility management function user equipment NG application protocolidentifier (AMF UE NGAP ID), and wherein the UE ID comprises the GUAMIor an AMF UE NGAP ID.
 3. The method of claim 1, wherein the identifierof the UE comprises a globally unique mobility management entityidentifier (GUMMEI) or a mobility management entity user equipment S1application protocol identifier (MME UE S1AP ID), and wherein the UE IDcomprises the GUMMEI or the MME UE S1AP ID.
 4. The method of claim 1,further comprising: transmitting, to an O-RAN central unit-user plane(O-CU-UP), a bearer context setup request message including the RAN UEID.
 5. The method of claim 1, wherein the UE ID is stored in the RIC,and wherein a list of UE IDs based on the stored UE ID is transmittedfor policy information from the RIC to a non-real time RAN intelligentcontroller (NRT-RIC).
 6. A method of a near-real time RAN intelligentcontroller (RIC) in a communication system, the method comprising:receiving, from an O-RAN central unit-control plane (O-CU-CP), anindication message for a report, the indication message including a userequipment identity (UE ID) and information associated with a UE per theUE ID; and storing the received UE ID, wherein the UE ID comprises aradio access network (RAN) UE ID for identifying the UE uniquely for E1interface.
 7. The method of claim 6, wherein the UE ID comprises aglobally unique access and mobility management function identifier(GUAMI) or an access and mobility management function user equipment NGapplication protocol identifier (AMF UE NGAP ID).
 8. The method of claim6, wherein the UE ID comprises a globally unique mobility managemententity identifier (GUMMEI) or a mobility management entity userequipment S1 application protocol identifier (MME UE S1AP ID).
 9. Themethod of claim 6, further comprising: transmitting, to non-real timeRAN intelligent controller (NRT-RIC), a list of UE IDs for policyinformation based on the stored UE ID.
 10. The method of claim 6,wherein a bearer context setup request message including the RAN UE IDis transmitted from the O-CU-CP to an O-RAN central unit-user plane(O-CU-UP).
 11. The method of claim 6, wherein an initial context setupmessage is transmitted from a network node for managing a mobility,wherein the initial context setup message includes an identifier of theUE, and wherein the identifier of the UE comprises a GUAMI, an AMF UENGAP ID, a GUMMEI, or an MME UE S1AP ID.
 12. An apparatus forcontrolling an O-RAN central unit-control plane (O-CU-CP) in acommunication system, the apparatus comprising: a transceiver; and atleast one processor configured to: receive, from a network node formanaging a mobility, an initial context setup message including anidentifier of a user equipment (UE); identify the identifier of the UE;identify a UE ID (UE identity) of the UE; and transmit, to a near-realtime RAN intelligent controller (RIC), an indication message for areport, the indication message including the UE ID and informationassociated with the UE per the UE ID, wherein the UE ID comprises aradio access network (RAN) UE ID for identifying the UE uniquely for E1interface.
 13. The apparatus of claim 12, wherein the identifier of theUE comprises a globally unique access and mobility management functionidentifier (GUAMI) or an access and mobility management function userequipment NG application protocol identifier (AMF UE NGAP ID), andwherein the UE ID comprises the GUAMI or an AMF UE NGAP ID.
 14. Theapparatus of claim 12, wherein the identifier of the UE comprises aglobally unique mobility management entity identifier (GUMMEI) or amobility management entity user equipment S1 application protocolidentifier (MME UE S1AP ID), and wherein the UE ID comprises the GUMMEIor the MME UE S1AP ID.
 15. The apparatus of claim 12, wherein the atleast one processor is further configured to transmit, to an O-RANcentral unit-user plane (O-CU-UP), a bearer context setup requestmessage including the RAN UE ID.
 16. The apparatus of claim 12, whereinthe UE ID is stored in the RIC, and wherein a list of UE IDs based onthe stored UE ID is transmitted for policy information from the RIC to anon-real time RAN intelligent controller (NRT-RIC).
 17. An apparatus forcontrolling a near-real time RAN intelligent controller (RIC) in acommunication system, the apparatus comprising: a transceiver; and atleast one processor configured to: receive, from an O-RAN centralunit-control plane (O-CU-CP), an indication message for a report, theindication message including a user equipment identity (UE ID) andinformation associated with a UE per the UE ID; and store the receivedUE ID, wherein the UE ID comprises a radio access network (RAN) UE IDfor identifying the UE uniquely for E1 interface.
 18. The apparatus ofclaim 17, wherein the UE ID comprises a globally unique access andmobility management function identifier (GUAMI) or an access andmobility management function user equipment NG application protocolidentifier (AMF UE NGAP ID).
 19. The apparatus of claim 17, wherein theUE ID comprises a globally unique mobility management entity identifier(GUMMEI) or a mobility management entity user equipment S1 applicationprotocol identifier (MME UE S1AP ID).
 20. The apparatus of claim 17,wherein the at least one processor is configured to transmit, tonon-real time RAN intelligent controller (NRT-RIC), a list of UE IDs forpolicy information based on the stored UE ID.
 21. The apparatus of claim17, wherein a bearer context setup request message including the RAN UEID is transmitted from the O-CU-CP to an O-RAN central unit-user plane(O-CU-UP).
 22. The apparatus of claim 17, wherein an initial contextsetup message is transmitted from a network node for managing amobility, wherein the initial context setup message includes anidentifier of the UE, and wherein the identifier of the UE comprises aGUAMI, an AMF UE NGAP ID, a GUMMEI, or an MME UE S1AP ID.